Both are budget Chinese web dramas that are very short, historical and focus on very heavily implied GL couples.

The Legend of Yunze Special also has some of the plot points (e.g., rebirth) that In Another Life has.

In both dramas:

(1) the leads misjudge eachother and get off on the wrong foot, and later enter into a contract relationship;

(2) the leads are smart, competent, and relatively successful in their careers;

(3) one lead works in business or law and ends up working with the other lead, who is an idol actor;

(4) the ML has a secret medical condition that would jeopardize his career if it became known;

(5) the FL has a strong, bad-ass personality and always takes action when she observes a woman or girl being subjected to sexual harassment;

(6) the FL has skills (sign language / fighting skills) that unexpectedly benefit the ML's work;

(7) the FL has a close best friend who knows everything about her; and

(8) the ML's best friend is his colleague who knows his secrets.

In both dramas, one of the leads (who is straight) has a very close relationship with a friend of the same gender, which creates a misunderstanding that the lead in question is gay. That lead then gets put in a position where they are suffering harsh consequences from getting on the wrong side of idol fans. The leads end up in a fake dating arrangement to protect the lead in question from this situation.

In both dramas: (1) the leads are relatively competent and successful in their careers; (2) the ML's have a certain celebrity status (a famous painter vs. a famous actor); (3) the ML's each have emotional trauma and complexes (which are at least partly touch-based) that impact their careers, thanks to the actions of certain women from their past (e.g., their moms); (4) there is something about the FL (her sexual history or personal interests) that society would judge harshly but that the ML doesn't judge or hold against her; (5) the leads start off on the wrong foot and misjudge each other, but soon get past that and develop strong chemistry; and (6) both leads have people around them who have romantic interest in them - but it's totally one-sided.

Both are short, bingeable romance dramas with little filler, simple plots that shouldn't be taken too seriously (because the "plot" is mainly just a vehicle for the romance), and great chemistry between the leads.

The FLs in both dramas have bad-ass personalities and defy societal expectations regarding acceptable behaviour when it comes to how women should interact with men (particularly their romantic / sexual partners). While some of the FLs' "bad girl" persona is a front, their bad-ass personality and lack of shyness in the bedroom is real. The MLs are not at all put off by the FLs' reputation or forwardness.

In both dramas, the leads are smart and competent people, but with secrets or hidden agendas.

In both dramas, one of the leads risks death or serious bodily harm to protect the other lead from danger.

In both dramas, one of the leads (L1) approaches the other lead (L2) with secret intentions, misunderstands the relationship between the other lead (L2) and one of their family members, and temporarily thinks less of the other lead (L2) based on the misunderstanding.

In a story, the ML is supposed to be a destructive villain who falls in love with a noble lady (the FL of the original story). But the true FL (a modern day woman) accidentally gets sucked into the story where she takes over the body of a woman (not the original FL) and starts to interfere with the plot to ensure the right outcome. The "villain" ML softens and seems to fall for the true FL after she seems to fall for him first (despite her obvious interest in the SML, which makes the ML quite jealous).

Short dramas. ML is a powerful fighter with a serious demeanour. FL is flirtatious - definitely not shy. Both leads have an agenda and secrets. Both dramas focus heavily on romance and romance-driven sacrifice with very little plot or filler.

Both are historical Chinese dramas where the ML is in a position of power, fell in love with the FL after a brief encounter as children, and takes aggressive steps to prevent her from being with the SML. Both MLs are controlling, possessive and protective. By the end of both dramas, the FL is determined and ruthless.

The ML is a strong fighter who is sent to spy on the FL. The ML goes undercover to get close to the FL in a role where he is under the FL's authority. When the FL issues commands, the ML generally obeys and plays the role of a subordinate. The ML also becomes the FL's protector and saves the FL from harm on several occasions, even when it means risking his own life. And the ML does not let injury or illness get in the way of... intimacy.

One further parallel that is minor but amusing: the man who at first seems to be the ML's main romantic rival is later shown to have more romantic interest in a family member of the FL.

The FLs both come from rich and powerful families. They have built reputations for being cold, demanding, and prone to shallow flings. The MLs are both good looking and good fighters, and the FL makes it clear that she finds the ML attractive early on. The leads seemingly start out on different sides and the ML does not tell the FL about his connections to the most powerful people on his side. But the ML takes on the role of the FL's bodyguard and goes to extreme lengths to protect her from harm - even if it means risking injury or death. The ML falls for the FL quickly and has no problem with the FL's demanding personality (in fact, it seems to be one of the things he likes about her).

Both dramas are Chinese historical romances where the FL is a clever, strategic, beautiful and graceful princess who has to lie to everyone (including the ML) for a good reason.

In both dramas, the ML is strong fighter who falls for the FL quickly, respects her, and always defends / protects her - even if it means risking his own life.

And in both dramas the FL does not know that the ML is connected to the emperor and distances herself from the ML when she finds out.

But there are two major differences: ZGZZS is short and fast and (for lack of a better word) just plain horny. The Princess Wei Young is long with lots of characters, subplots, and repetitive themes and the leads have very limited skinship. They're both great dramas in their own way.

Noona romance. In My Fated Boy, the FL is a hard working executive secretary who puts more energy into her work than she puts into looking after herself / her apartment. In IHYV, the FL is a public defender. Although she doesn't put maximum effort into her work because she is jaded and expects the worst from people, her job is still demanding and she doesn't take great care of herself / her home is messy.

In MFB, the ML and FL grew up together and the FL protected the ML when he was bullied. The ML developed a crush on the FL and wanted to grow up to protect her, and held on to those feelings steadfastly as he was growing up. In IHYV, the FL helped the ML after a tragic event when she was a kid and he was a little kid. The ML fell for her then and vowed to protect her. The ML in IHYV also holds on to his feelings steadfastly.

Both dramas begin with the ML meeting the FL again after a long time apart, and moving in with the FL shortly afterwards partly to protect the FL but also because of their hidden feelings for the FL. Both MLs are young, energetic, clean (the type to comment on and tidy up a messy apartment), reliable and affectionate.

In both dramas the leads' parents were best friends so the leads grew up together before the ML went abroad to study. The ML returns and reconnects with the FL at the beginning of the drama, and moves in with her shortly after. In both dramas the FL is a bit worn out by her work and previous disappointing relationships. And in both dramas the ML is bright, energetic and brings a spark of joy back into the FL's life.