If I were to end up doing it (too many things I would like to do, too little time), I’d do it foss. At most I’d paywall features that have an ongoing cost (like hosting or server costs), though I am a bigger fan of keeping things local. That way its simpler and also easier to trust.

Personally, I think that paying for software isn’t a bad thing as long as the price is right and the licensing reasonable (I really hate unnecessary subscriptions). Devs (specially if working on complex stuff) got to eat too, and sometimes donations aren’t enough.