It's not really out of control or complicated at all.
> Then every dev tool pastes some config into some of these config files.
This is why you see it to be complicated. Don't do this. The only thing you should really ever be editing is $PATH, and even then I'd argue not to. Do something else. Use direnv, source .env files, write wrapper scripts.
I don't put arbitrary shit into shell profiles or shell rc files, you're just asking for pain.
You should understand what you're doing before pasting arbitrary bits into these files.
