I've reached a skill plateau where I can easily get to top 20-30 on my belly, coming as high as 4. But if I don't engage in much combat along the way, I tend to end up with only a shotgun and/or SMG in the endgame- which seems inherently balanced.
I feel like there are several walls you run into as you play this game. At least that's how it's been for me, though it might be a different learning curve for people that take the approach of dropping in highly contested areas to get better at the gun play.
The first wall is being able to get into the end game (final 10 or so) with some regularity. The next one is being able to make it into the last 1 or 2 circles when there are only 2-3 players left. The last one is winning your fair share of those final showdowns.
If you are getting to the final 20-30 players under-geared you may not be looting enough in the early game. Your strategy may be different, but I try to get far away from the plane path and somewhere where there should be plenty of places to loot. The first circle placement and whether or not you find a vehicle will have some affect on how much time you have before you need to move on. If I don't think I have the right gear/items to have a fighting chance in the end game, I'll keep searching until I find what I need or die trying. Hunting and killing someone else for their gear is an option too. No sense stealthing my way all the way to the end game only to not have much of a chance because all I have is a pistol and a shotgun. Again, strategies may vary but my goal is always to find a backback, helmet, armor, 1 gun that can hit at least mid range, 1 gun that can go full auto for short range (shotgun would be ok here if you like shotguns...I don't), a decent enough amount of health and boost items, and ideally some optics and upgrades for my guns. Usually I find an adequate load out just from looting away from the plane path but sometimes the RNG is less kind and I need to continue to loot even as the circles converge and it's more risky. Finding a vehicle is nice because you can relocate to yet another safer area away from the plane path if your first area came up short.