It sounds like you ought to be gotten at least one experienced team member an M1 laptop, and asked them to spend a 2-3 days making sure that you software runs smoothly on it.

Our software at work didn't work out of the box on M1, but fixing it was fairly trivial and mostly involved upgrading library versions (although we use Node not Python which admittedly tends to be better at portability). But someone completely new to the codebase definitely isn't the person to be fixing these issues.