I second The Romance of Tiger and Rose but (as of today) subs are only up until ep #22. If you enjoyed ZLS in Love Better Than Immortality, she's better in this. Still cute but not as annoying...
As for 2020 titles, these are on my to-watch-next list after TROTAR that also look like the same theme you've a hankering for: Love and the Emperor, My Fantastic Mrs. Right
I've found that c-dramas have been hot on this since lots of current Chinese readers like these isekai-style stories. Lucky us! How have you NOT watched The Eternal Love yet?!?! I know it's not a 2020 release but it's a must watch for everything you want, even if she doesn't have everyone loving her cuz she's such a brat, haha. It starts off with her waking up in the parallel universe & proceeds with a well-paced storyline into sheer fantasy. The MC's chemistry is GREAT. It's even got a Season 2 where they start in the present-day and she returns to the parallel world. It is the drama that hooked me on these types of stories so I highly recommend it. :D
Based on your list, I would recommend these similar story lines from the last couple of years. (Both are romances with a lot of comedy.)
1.) Oh! My Emperor (more ZLS but cutesy-ish, so not as mature)
Naiwen:
handsome, cute and sexy MLs in ancient Asian costumes
And oh-my-my-my does it have this in SPADES. She has the entire boy band XNINE at her disposal. ;)
2.) Unique Lady (here, it's a "video game" past version of the world she enters in to discover love)
Naiwen:
modern smarts, optimistic attitude on life
She's pretty funny, too. Our ML (Simon Gong) is the perfect childish bully-turned-yandere in this but she has many other attractive men in costume since she's meant to choose between them.
I would love someone to start an isekai-style c drama recommendation list, actually! :)