The one for reddit is :https://rdx.overdevs.com/ I think nitter was like this too ? Not sure as i have never used it or is just a site to see the posts sent to you ? I think piped works in this same manner for youtube so going to link a client too : https://f-droid.org/packages/com.github.libretube/ . I know barinsta used to be a thing until zuck went after the dev so is there any instagram scrappers now i would love one because then i can actually see what my friends sent me or know what their up to .
If the site isn’t too JS dependent, you can browse with something like lynx and that helps. Otherwise decrapifying tends to be site specific. I’ve done a few for sites that I frequent, but it is tedious. Alternatively you could use archived snapshots.