I don’t know if calls work, but all the other stuff you mention does work.

I have an old device in the closet and use the matrix bridge. The bridge bot kindly reminds me to turn on the phone every 12 days, but I think WA’s requirement is 15 days.

I do have to ask though: other than basic text chat, what else does WA offer these days?

For the record, I’m able to see videos, images and listen to audio. Haven’t received a poll yet. Is there anything more to it?

Missed your post before the edit. But I’d like to read your rant on Matrix. Even if it’s just a TL;DR.