Can you guys recommend me manhwa with the most red flag seme? :))

Try these:
https://www.mangago.me/read-manga/jinx/

https://www.mangago.me/read-manga/stockholm_syndrome/

https://www.mangago.me/read-manga/love_jinx/

https://www.mangago.me/read-manga/lima_syndrome/

https://www.mangago.me/read-manga/speak_of_the_devil/

https://www.mangago.me/read-manga/double_trap/

https://www.mangago.me/read-manga/big_apple/

https://www.mangago.me/read-manga/wet_sand/

Jinx
legs that won't walk
love jinx
Placebo
Sadistic beauty bl sidestory (i just heard the seme is a red flag)

Those are all green flag to non zero sum

Just hate how recommendations these days are so stagnant red flags semes have been done better than jinx my godd read Warehouse

Palace of Bardo
The Beast Must Die
Ventham

Not sure if I would recommend but definitely red flags:
Fruit of the Tongue
Abyss
Obey Me

https://www.mangago.me/read-manga/hogu_hagyeongsu/
https://www.mangago.me/read-manga/no_reason/
https://www.mangago.me/read-manga/color_recipe/
https://www.mangago.me/read-manga/wish_you_all_the_best/