with a lot of low-effort unreal trash games that all look the same and doesn't have good artistic direction nor game mechanics.
I think this is because unreal gives you so much by default that the developer doesn't really push any boundaries and innovate. Case in point : movement from different games made in unreal all feels "the same".
of course you can achieve any art style. I'm saying that low effort games you can find on steam, for example, don't do this.
Contrast this with more ambitious games and you'll usually end up with an array of custom shaders, a stack of custom post effects, etc. That really lets you define a look that's all your own.
Is this really a problem? Would we be better of if the process was a lot more difficult?
On the other hand, even if you use cookie cutter approach to game mechanics you could make other stuff more unique (like story or universe).
The lower the barrier of entry, the more people have the opportunity to try their hand at game development. That means more developers providing more exciting ideas! It might mean there's more low-effort stuff out there, but there's always been tons of low-effort stuff out there, anyway.
People are often complaining about a lot of poor quality stuff on the market. I don't actively seek it out and I rarely come across it. So, why would it bother me?