I'd suggest "first party isolate" here. The feature restricts cookies, cache and other data access to the domain level so that only the domain that dropped the cookie or file on the user system can access it.

I removed Decentraleyes and just have FPI enabled.

Also, this is pretty much I do after installing Firefox. https://github.com/arkenfox/user.js/wiki/4.1-Extensions

I have seen something like what you explain here, except extensions: https://github.com/grzegorzk/ff_in_podman