The problem I see with federated wikis is potential creation of echo chambers. Current Wikipedia is often a political tug-of-war between different ideological crowds. For instance, on Russian Wikipedia, Russian Civil War article is an infamous point of struggle between communist and monarchist sympathizers, who often have to settle at something resembling a compromise.
If both sides had their own wikis, each would have very biased interpretation of events. A person who identifies as either communist or monarchist would visit only the corresponding wiki, only seeing narrative that fits into their current world view, never being exposed to opposing opinions.
I also run a lot of proprietary stuff like Discord or Instagram due to peer pressure but I let it slide and put my hopes on Android sandboxing the apps and GrapheneOS tweaks. In my opinion, making sure that proprietary app can’t reliably access your data and never giving it anything sensitive yourself is a decent risk model.
The only proprietary software I use and somewhat trust is Obdisian. Honestly, it’s just excellent and I can’t see myself moving away from it anytime soon.