The closest I know about are:
https://wiby.me/
and
https://search.marginalia.nu/

Unfortunately Mozilla doesn’t seem to be opposed to the attribution, only the implementation. They have their own proposal called IPA:

https://blog.mozilla.org/en/mozilla/privacy-preserving-attribution-for-advertising/

https://github.com/patcg-individual-drafts/ipa/

pcpartpicker is a fantastic resource for putting together a new build.

As far as lemmy communities go, there’s also !buildapc and !buildapc

Also, the reason people throw out the 90% figure is because that’s about what it was at the time. Granted most of the rich still managed to only pay ~70%.

Here’s a couple jumping points: Historical chart, US tax history on Wikipedia

Kbin allows user-level instance blocking, so that functionality should be feasible to implement in lemmy eventually.