your recommendations for someone who hasn't seen many jdramas?

Since you like 5-ji Kara 9-ji made, try Takane No Hana for more of Ishihara Satomi

I didnt watch a lot of Japanese dramas. Those are among my favourite dramas of all time, some are very old though:

https://mydramalist.com/2-1-litre-no-namida -very sad

https://mydramalist.com/1344-asuko-march -quite interesting plot about a girl who goes in the technical high school with mostly "bad boys" and bad reputation

https://mydramalist.com/11189-dear-sister -sisterhood/family drama

https://mydramalist.com/25-gokusen -quite interesting imo, about new teacher who becomes homeroom teacher of the worst class. And she is a heir of the yakuza clan too. There is a lot dramas with similar plot, if you like those types, I can recommend you more.

https://mydramalist.com/51965-koi-wa-tsuzuku-yo-doko-made-mo -GREAT drama and newer than any in this list. You should definitely watch it.

https://mydramalist.com/56-tatta-hitotsu-no-koi - I LOVE this drama. I find it very romantic and simple, but amazing in it's simplicity. It is very old though... Rich FL/poor ML

Those are my favourites. You have also dramas which almost everyone watched first like Hana Yori Dango, Hana Kimi, Itazura na kiss and such... But I, personally, dont find Japanese versions of it the best. Maybe only this 1 https://mydramalist.com/2985-hanazakari-no-kimitachi-e

i loved most of the others recommended in the comment section but if i would add more def you have to watch:
romance i would suggest  good morning call, koi wa tsuzuku yo made mo and love phantom 
other genre but i loved: Tengoku to Jigoku: Psychona Futari  , todome no kiss and Algernon ni Hanataba wo , gakkou no kaiden