So recently my mom and I started watching kdramas together and she’s obsessed! But she’s also a bit picky, so I don’t know what to recommend now.

She really liked suspicious partner, healer, welcome to samdalri (she’s a ji chang wook fan lmao), while you were sleeping, tastefully yours,  25 21 and undercover high school.

I tried making her watch Vincenzo since it’s obvious she’s gonna love it but she didn’t like how he looks like a villain in the first episode and decided to drop it (sigh). I’ll try again sometimes 

She’s not really into fantasy (had to convince her to watch while you were sleeping, she loved it after a couple episodes but any more fantasy than that she wouldn’t like). What she likes most is the cute romance. She loves characters with like a fun personality but not to the point it’s cringy, like the main characters from the kdramas I mentioned. She likes most genres as long as it’s not too fantasy (like she’d absolutely hate something like extraordinary you, sadly). Any recs??

'Our Blues' is a strong recommendation from me personally....some other dramas according to your descriptions : "Start-Up", " Twinkling Watermelon","Our beloved summer""Hometown Cha cha cha"

My mother is extremely picky as well, has similar restrictions/taste too lol. Try: 

What wrong with Secretary Kim ,  ( Mom loved this)

Touch your heart

Both are cute office romcoms.

Eulchacha Waikiki ( Very funny, also has one of the cast from healer, younger version of villain in parents friend group  the jelly one lol)

Weightlifting Fairy Kim Bok Joo 

The First Frost  (This is a C- drama, I haven't watched this yet but I read the web novel, it's really good. The reviews are very good for it too.)

Also if you can  get her to watch it she might also like:

 I hear your voice ( similar to while you were sleeping in supernatural levels, Also same ML, Lee Jong suk),  

W 

and Chicago typewriter (   W and this one, some of my mother's and my favs, both have some supernatural but I find them not over the top, if that makes sense). My mother  really loved these two surprisingly well.

Hope these are useful.