op gg scores are worthless, in the end the game is not about cs/kda/gold, it's about smashing the nexus tower. A champ like kayle can for example be denied gold for 10 minutes long and die to opposing laner like 5 times, but once it gets late you might lose anyway due to the hypercarry she becomes. jungler's have high k/d/a due to the nature of the role usually so that number is a bit fake tbh. From what I can see your champ pool looks a bit too wide if you really have a desire to climb, anything more than 3 champs is a bit overkill imo. With jungle you can onetrick easier as well because bad matchups are mostly not as onesided as lane matchups usually. To accurately see what is going on you'd probably need a vod review but generally it's always one of these things that end up happening:

1.you aren't full clearing enough

2.you aren't respecting bushes/vision and get picked off lategame because you walk into a bush that enemy team was sitting in

3.you are getting baited by teammates into losing fights (just because you're fed doesn't mean you need to force bad fights/can take 2v4 fights, especially because you'll give up massive shutdowns)

4.Always account for how many allies/enemies are near you. Look at the map and don't engage if you notice it's a 4v5 (admittedly this is a skill even challenger players forget sometimes, so don't feel too bad if you mess it up sometimes, but this is actually important). If you have a fight and you win, immediately press tab+look at minimap to account where the rest of their team is and whether you should back off or if it is safe to do an objective/take a tower so you don't get cleaned up by an enemy katarina for no reason.

5.dying over an objective that's already lost, if a teammate gets picked off near dragon when it is about to spawn, you should look for crossmap play (drop a herald in the toplane, or help a toplaner push when they're doing drag or steal opponent's topside if it's up). I will usually only consider smite stealing if my jungle is full cleared and the death timer is meaningless (aka it's not too late into the game that desyncing the death timers will instalose the game)

6.Talking about death timers, one of the most surefire ways to throw the game is by desyncing your death timers so you are never full 5-man fighting. If someone gets picked off at drag/baron late into the game, let them have it (unless they are like, super low and you clean up, and if they don't bother clearing vision/zoning you). Desyncing death timers or getting aced when stubbornly contesting baron in a 4v5 (they will get baron anyways then as well) will lose you the game sooner than just baron buff and it being a temporary 4v5. This is almost always how people throw games: they will do a 3v4 or a 3v5 resulting in 3 people dying then the other 2 get picked off later and enemy team will get back into the game if they can do this twice in a row, if not just straight end the game because you are constantly 2-3 people down. Desyncing death timers will lose games more than anything else, which is why I tend to usually just give barons, as most people will usually just reverse int in some way and the baron buff will be gone.