Squeaky voice with Microsoft Teams on eOS and iodéOS

On both Android phones I own (all systems up-to-date), MS Teams calls are not usable, since the caller voices are all squeaky. I have the impression that a compression algorithm in the background is not doing its job properly. The phones are a Fairphone 4 (with the latest eOS) and a Fairphone 3 (with the latest iodéOS). The problem occurs every time someone calls, both with and without video. Everything else seems to be working fine, just voice is unusable. Some internet searches reveal that the issue might not be related to MS Teams itself, but I doubt that, since normal calls and VOIP works just fine. So the question is: is there a workaround, some package that I’m missing, or is MS Teams plainly incompatible with de-Google-d operating systems?