Help Mic from one device while using speaker from another?

I fly a paramotor with a helmet that has an integrated bluetooth headset. The problem is the noise isolation isnt great so I want to use some bluetooth ear buds. What I would like is to be able to play the audio out of the ear buds while using the helmet's mic for the phone calls. I have a Galaxy s21. I see that I can connect both devices at once, and can even play my music out of both speakers at once, but if I start a phone call I seem to have to choose between which device to use and can't use both.

Is there an app or something I can install to let me use the mic from one bt device while directing the audio to another while on a call or playing music?