I do sometimes see AMA’s being suggested on Lemmy, but none that i personally checked out, so i don’t know how many people respond to them. My guess is that it would probably depend more on how active a particular community is, since there doesn’t seem to be a dedicated AMA community here, rather than a smaller user base. Some communities are not very active, others are very lively. As for an AMA for Proton, i don’t think they have joined lemmy yet and unfortunately, no one on reddit asked them to join here :-(