Back to pulseaudio and following > https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/1247
first answer by Igor Kovalenko I edited /etc/pulse/default.pa to match load-module module-bluetooth-discover enable_native_hfp_hf=falseand with that parameter (enable_native_hfp_hf=false) things are back to normal. Couldn't find out what the equivalent setting for pipewire would be, that's why I went back to pulse.
Positive side effect: ofono seems not to be necessary anymore.