“It doesn’t work for me.” Your argument is also just an anecdote.
Personally, I love OsmAnd because of the power features. In the best sense “it works for me”. However, I would recommend OM to not-so-nerdy friends and family as it is just simpler to use and understand due to the fewer features.
I don’t think this is true in that sense. You can get the full experience for free by - either building it your self - or simply on FDroid. If you still use Gruesome Playstore, then yes, it is “soft paywalled”.
Or do you mean other features that are not even in the FDroid build? (Which could be some proprietary features.)
Short answer? No and no.
If you have a fully open source product (with a permissive license) you can’t just “paywall” it, as FOSS licenses allow you to build and often redistribute the product.
When you have a fully open source product and want to build a valid business model from it, you have to work WITH your license. The OsmAnd team chose an interesting way to do this by “paywalling” the Playstore version “OsmAnd+”. But you still can get all the stuff, as it is open source.
https://en.m.wikipedia.org/wiki/OsmAnd#Licensing
Welcome to the world of FOSS. 🌍