Some recent dramas you should watch :

Kill It- action, thriller drama with great cast and OST

Touch Your Heart- romantic comedy with couple reunion Yoo In Na and Lee Dong Wook (from Goblin)

Her Private Life- romantic comedy with great Park Min Young 

similarly to you i have also been away so I am anticipating what will others recommend :)

I recommend SKY Castle it has almost all your preferred genres and it created a lot of buzz when it was airing. It'S from JTBC so it had usual cable TV viewership ratings when it started airing (around 2.0%) but then it became one of most watched cable dramas in the history (nearly passed 25%)

I am also currently watching WWW: Search and it is really enjoyable adult romance + sismance + office story

Tomorrow starts airing IU's newest drama Hotel Del Luna and it looks pretty interesting - i'm anticipating this drama a lot.

Some new-ish Jdramas that I liked and you haven't watched (based on your drama list):

Beautiful World had its flaws, but overall was still quite good and hits a lot of your criteria: family, friendship, and school.  But it's a melodrama, so maybe it's not quite what you're looking for