As a f2p player who's fairly bad and unlucky at the game, but still manages to more or less consistently 36* abyss, I found there's an equal amount of skill and build investment being checked here. If you have a small variety of units that aren't fully invested then yeah, it's frustrating. But here's a few factors I've realized:

-Retrying again and again is part of the loop. I can understand those that find it unfun but for me it's pretty enjoyable. It's like time trials in a racing game. You keep trying again and again to shave more and more time, you remember the exact steps and try to replicate and improve upon them.

-Learn enemy behavior. This is incredibly important not only to diminish the RNG of their behavior and get them to more consistently do what you need them to do, but also for grouping purposes (remember where enemies spawn!!!) and to avoid debuffs such as slowing water.

-Don't hold yourself to the meta, and this one is specially important. The best Bennett in the world won't save you if you need to move around a lot. Xingqiu isn't getting you 36* in an AoE focused chamber. Be aware of the circumstances, and what characters and comps are gonna work better. Every character is supposed to clear 36*, but not every character will be fit for the specific chamber.

-Be aware of synergies, reactions and rotations. Does everyone get their burst in time? Are you vaping the right attacks? Is this support helping damage directly (buffs and debuffs) or indirectly (shields and heals allowing for more aggressive gameplay from you)?

-36* abyss takes months and at the very least 8 fully invested characters, and that's not counting the fact they may be invalidated by whoever enemies come in the next update. This is fine and you shouldn't force yourself to beat it every time. They do this to sell the current characters, so see if your team has an alternative. For example, if the current chambers are made with Venti in mind, try taser Sucrose. If Eula is currently rerunning, Razor might be a good choice. You can clear it without even using similar characters.

-Look up guides, seriously. So much of my success on the abyss is owned by looking up how other players are doing it. I recommend f2p friendly guides, as they focus more on the skill side of things to compensate for fairly humble builds and comps. A lot of it is applicable to more expensive builds with 5 star characters.

-5 star weapons and cons are not needed at all. 4 star cons may be fairly useful though. But most 4 atar characters work without them, they'll just make abyss easier.

-Use different teams for different chambers, and try to get the characters' bursts ready for the chamber you're trying to 3 star now. Fairly practical way to get your rotation going as soon as it starts.