I'd like to see some "realistic" drama (like Misaeng, Romantic Doctor or Age of Youth) or something facing some social problems like bullying, bribery...

Are also fine historical drama that are faithful to the historical reality

Nothing too much romantic, I hate love stories.

Any nationality is ok.

Thanks in advance!

Hi! :) I'd recommend...

Good Luck!! ---> life and a bit of romance
Dragon Zakura ---> studying related..
Kingyo Club ---> school bullying...but there's a bit of romance also. Still the drama has 10 eps and each ep is 20 mins :)
Limit -->  bullying/survival

and if you don't mind drama specials..
Drama Special Series Season 2: SOS - Save Our School ---> bullying 
Myu no Anyo Papa ni Ageru ---> life/illness


Hope you enjoy! :)
Kazoku Game
Punch
Nobuta wo produce
1 litre of tears

Arifureta Kiseki
My Girl (the 2009 Jdrama)
Blossom (the 2016 kdrama)
Nemureru Mori no Jyukujyo
Return of the Cuckoo
The Homeless Student
Jejoongwon- about a real doctor and a real hospital when modern medicine was first introduced to Korea.
I'm not sure how realistic it is, but Angry Mom definitely deals with bullying and corruption, and doesn't have too much romance.
Candy House - no romance
Golden Time
- no romance
Thank You - child's illness
I'm Home - already a married couple, a bit reallistic
On The Way To The Airport - i liked the way the situations unfold in this one, this is the only one from my recommendations that is a major romance drama.
Late Night Restaurant - not serious but serious,