I played a little with the end-to-end encryption app in NC 21.0.2 and E2EE app 1.7.1 with stable desktop client (06.2021) and it looks sharing is completely disabled once you encrypt a folder… the folder replicates well between different clients of same user but there is no way to share the folder with another user… this should work by design but most likely it’s another bug now… it looks it doesn’t work now. the web page shows it as planned per “early 2021”
my conclusion is e2e is not complete now… I would expect much more mature solution 3y after they started working on this functionality… I suggest you choose another solution for now…