Same problem here since I buyed FP5. Latest version of FP5 and WA. In a crowd just annoying, that anybody can listen to the calls. Just tried also the mentioned possibilities, but none of them solve the problem.
Yes I have tried uninstalling WhatsApp. But it is more than WhatsApp it does it, also MS Teams. Also new fair buds don’t work with MS Teams which I’m not sure if connected but I’m looking into