The alternatve is to do "cleanroom writing": you don't interact, therefore if you write something similar, you can argue you independently invented it.
I had the same problem in a scientific research lab where collaboration with another lab runs the risk of not being able to patent an idea, because if the other team had the same idea or anything close enough to it, we couldn't claim to be the inventors.
If I somehow recreated Lord of the Rings from scratch, without having known about Lord of the Rings, it wouldn't be copyright infringement because I never copied Lord of the Rings.
The issue is nobody would ever believe me when I said I coincidentally recreated Lord of the Rings from scratch. The court would conclude I copied Tolkien's books without permission.
If you admit to reading fanfiction, it reduces your credibility when you claim you independently came up with the same ideas as fanfiction authors.
This increases your litigation risk, but there's no black or white rule that you need to pay every fanfiction author or anything like that.
> The issue is nobody would ever believe me when I said I coincidentally recreated Lord of the Rings from scratch.
What do you mean? They believed Terry Goodkind; why not you?