How can I forward audio from the handset mic to wireless earbuds

Im involved in a kind of cosplay where it’s useful to have someone else relay verbal instructions from the sidelines. (Very heavy sound deadening helmet)

Because its in a small space, and I can’t carry a handset, I can’t set it up as say, a VOIP chat or call from their handset to mine.

So what I want is a way that I can pair some Bluetooth earbuds to a handset, and someone can talk into the handset mic, and it’ll be relayed and played out on the bluetooth earbuds, which will fit discreetly under the cosplay. (I can modify the helmet to ensure space inside if needed).

Is that something Android can do natively, or does it need a visit to software recs stackexchange for an app to do it?