Like "Light, Saimdang's Diary" , "My only Love Song), (currently watching), "Scarlet Heart Ryeo" (finished like years ago, also finished Gong 1, 2 and all the Chinese, Japanese versions) and "Faith", by Lee Min-Ho, or anything else than Chinese  (been binging too much Chinese dramas lately, lol) is fine (any other Asian countries (like Thai, Japanese, Filipino and etc?) historical romance time-travel dramas).

I know Faith and Scarlet heart, both are more "main FL goes to past in first episode and whole plot is there",  this case is in "Mr. Queen" though it's quite different, as a drama I would say much high quality without chlices and primitive plot turns, with quite mature subtexts btw )))) very funny and FL is most unforgetable character (she and FL from "it's okay to not be okay both are most different amazing FL's who you never forget)  and on of greatest act from female lead/actress. really must watch. about romance, it's not a drama that you watch for romance but I think it's one of most provoking romance and drama makers put there many quite mature subtext details, nothing big for plot but .... 

Nine: Nine Times Time Travel  not historical and not "geos in 1th ep. and stays" but actually real time travel and really great drama, with mature/realistic romance and natural chemistry, interesting twist and turns till the end.

Hit the Top also not historical, pop star from 90s in modern world. God, it was such a great watch, funny, good romance and one of most amazing and hilarious ML <3

One More Time not time travel but time loop (like groundhog day). it's Netflix series, really high quality, not cliche, realistic story and romance, really really good drama and romance (especialy if you tired with same plot faritale romances)

Kairos  no romance and not time travel but 2 people in different time communicating to change terrible events in their life change. Great high quality drama and amazing acting, interesting twist and turns till the end.

I just saw last part, that you want historical, so I haven't seen it but I think it's perfect fit https://mydramalist.com/3985-queen-in-hyuns-man


though I highly recommend dramas in previous massage, at list first 3 )))

Alice  - One of my favorite of this genre. Though I'd prefer to call it the Parallel Universe genre since it kinda lessens the controversy people try to rile up on this one. Not Historical.

Familiar Wife (K-Drama) /  Shitteru Waifu (Japanese version)  - Not historical but I'll highly recommend it. Both are good but the Korean version like always more draggy. Not Historical

Hello, Me!I dropped at a certain point. But seems like people rated it good. Not Historical.

Nobunaga Concerto  - Japanese Historical Drama with time travel.

Ashi Girl  - Same kind as the above.

If you're strictly looking for time travel(and historical), then I can't name stuff like Time Rift/Manipulation type movies which are all great. :(
But, I'll still name em(since I can). ^_^
 Il Mare
Cafe Funiculi Funicula
Ditto, Hatsukoi Loss Time
Until I Meet September's Love
Tomorrow I Will Date With Yesterday’s You
How Long Will I Love U