Tryndamere kind of sucks now
He was always kind of iffy, a little too unreliable / feast or famine.
But right now he's particularly crappy-- don't know why, probably dozens of factors tbh. Just feels like there is too much counterplay to him, and I can't imagine a healthy game where there isn't, so he likely needs a rework or atleast some adjustments to his kit.
His R isn't even that big of a deal, its just his R + the rest of his kit that make him so binary, specifically his tendency to dive a single target / chase people down while immune to death. If he didn't have such high sticking power, Undying rage really wouldn't be that big of a deal from a balance point of view-- it could even stand to last a lot longer than it does (assuming he doesn't get to keep his 60% 4 second slow and a short cd dash)
idk, i just feel like tryndamere will never 'feel' like he belongs in league (always too much counterplay / has to split push all day and can't do anything else reliably / extremely oppressive when ahead and total garbage when behind / goofy rng in early laning phase that dictates most of the game) as long as his kit is the way it is.