Yaoi but can be straight or gl? So are you asking for yaoi, straight, or gl? I hope you know what yaoi means.
Anyway, here are recs (Yaoi):
https://www.mangago.me/read-manga/a_trace_of_the_wonder/
https://www.mangago.me/read-manga/from_points_of_three/
toxic yaoi with good ending. Ok
I guess for bl manhwa/webtoons
Blind Play
(they both know they're heading the wrong way. I still love the story tho)
Painter of the Night
(the ending was so bittersweet in a good way)
Some of my top fav toxic bl:
Legs That Won't Walk (previous person already rec this)
(this is just crazy, like how far did you have to go to hurt someone you love like that? It makes me cry internally thinking about them sometimes. All the seme are hot, uke is also hot lol)
https://www.mangago.me/read-manga/legs_which_cannot_walk/
The Beast Must Die (a tragic beginning, one of the most romantic and passionate duo imo, satisfying ending, everything's flawless)
https://www.mangago.me/read-manga/the_beast_must_die/
Love or Hate (pseudo incest, it ruins the nuclear family and everyone's hurting. The ending is good at least in my opinion. Love every bit of it)
https://www.mangago.me/read-manga/love_or_hate_yeongha/
A Fine Line (bratty seme, patient mature and older uke. This is a lighter and tamer one, not extremely toxic, the ending was ok)
https://www.mangago.me/read-manga/a_fine_line/
I'm sorry, I just woke up and realized my mistake. You may be asking for toxic straight and toxic gl（/TДT)/
Straight:
https://www.mangago.me/read-manga/your_eternal_lies/
https://www.mangago.me/read-manga/failed_to_abandon_the_villain/
These aren't as toxic as some of the yaois are, but still toxic (imo)
Oh no I said it wrong haha, I forgot to remove but can be hehe.
Do yall have any toxic yaoi with good ending, it cam be straight or gl