proprietary apps

There’s your problem. Replacing american closed-sourced apps with european closed-sourced apps is not the solution - usually, an american open-source application is going to be a better alternative than a european closed-source application. European commercial tech (if you can find any in the first place) rarely sees an issue with sharing data with US tech companies, which is a lot worse than e.g. using Signal, which right now still seems secure and doesn’t share any metadata (which it supposedly doesn’t save in the first place) with US companies or the US state. This is the reason why we’re on lemmy in the first place!

So, for app stores, F-Droid is the go-to store for open-source apps right now, though some projects also offer standalone APKs (e.g. Signal).