What the fuck is this even actually about? I've been following this for quite some time no...

I can't believe im gonna explain a yaoi comic but here we go.
The black haired dude (jinha)
And the twink (won)
The other black haired dude-big bro- (jinseo)

Won has various mental disorders due to him being abused by his father and because he was groomed by a teacher into thinking that being hit is a sign of love.
One day he meets jinha (when jinha was a KID btw) he grows attached to him bcuz he took care of him after he was having an episode and scratching himself.
Years pass and he has no clue where this kid went but in college he meets someone identical to him; jinseo.
Turns out jinseo is jinha's big brother.

Jinseo fw won heavy so he pursues him romantically and won agrees to date him just to get to jinha. (Jinseo thinks won fw him too)

At some point Jinha finds them fucking (won and jinseo) and he realizes he fw that gay shit so he starts to develop a crush on won.
Won pulls a generational trauma move and starts to tutor jinha (basically grooms him yk)

Won is a pedophile so he starts making jinseo wear similar clothes to jinha which makes jinseo angry and forbids won from meeting jinha again or tutoring him.

Fast forward some time in the future idfk, jinseo pulls some silly drama tactic to prank his brother.
(He ties his bf-won-in a closet for jinha to find) and when jinha realizes it's a prank he gets embarrassed and rushes off only for his big bro to push him down the stairs (k-drama style) and lose his memories partially.

Okay fast-forward again the big bro is dead and jinha has little to no idea who won is (jinha only remembers the moment he caught them fucking) and so he is romantically interested in him.

Since jinha doesn't remember anything he goes through a bunch of shit that makes him anxious as he feels as if hes messing something BIG (which he is)

So he starts tweakin out which makes won leave for the Bahamas for a bit and return which tweaks out jinha even more and so won allows him to break his ankle so he can feel less anxious.
And TA-DA!!! they fuck. More than one time.
That's it basically.

Won never agreed to date him; he agreed with be his sex friend

How the older brother die anyway? Accident or suicide?

Suicide

Reason?
I wanna read it but, is it worth it?

The big brother called Jinseo realised that Won, his sex friend, is actually in love with his little brother, so to make Won suffer, he killed himself.
Let me warn you/give you a trigger warning: the webtoon depicts cycle of grooming, child abuse and domestic abuse.
Won, the silver haired guy is a gay man victim of his father's abuse, and his tutor groomed him. When he got fed up by everything, he met Jinha (the main protagonist) who was a teen (13), and because of his kindness, won, who was 19 almost 20, fell in love with him. And waited years for jinha to become an adult.

The atmosphere is heavy and the plot keeps your attention but I don't blame people who stopped reading it because of the grooming and pedophelia

I gave a few glances to your list (that I like) and I doubt that you may like this webtoon :(