They are both:
-Korean
- Zombies
While Kingdom differs from All of Us Are Dead, for the fact that it's a historical drama, don't let that throw you off. I would highly recommend Kingdom and would even argue it was better that All of Us Are Dead. (typically I don't watch historical dramas but kingdom is just so good it's 100% worth it).

- high school setting
- the ml of both are "loners". In color rush, the ml is starting at a new school and he's different from everybody else/ isn't really interested in friends.
- are both shorter episodes/ miniseries
- the ml and second ml both kinda rely/ need each other
- They are fluffier or leave you happy but also both deal with very series topics and can get deep.
- both bl
- lots of flirty swoonworthy moments
- just give me very similar feelings

I'm not fully sure why, but I kept getting reminded of cherry magic the whole time I was watching this. I don't know how to describe it but they have very similar vibes.
- two main leads work together
- in an office setting
- a main plot besides plain romance
- acknowledgeable character development
- an overall fluffy feeling
- Both couples basically keep their romance a secret from work (at least marriage honey for beginning episodes)