It doesn't matter to me personally if it's open source. (There does seem to be some binary blobs involved in their software according to the cryptpad dicussion link I posted above. That I do not like).
I only mentioned it because it is a "thing" even though it is not my thing.
I think - we need to have software - not subject to political gimmicks - since countries can get into wars with each other & sanction each other etc
remember when Venezuela was sanctioned and they couldn't access Adobe 360 or whatever it's called.