Glyphs 3 / Python 3 / M1

Also I cannot install pyobjc Ising Georg’s method (it seems to attempt to install the latest pyobjc 7.1 but gives me an error). Error messages are quite long and I don’t know which part is relevant.
It may be too soon but I would greatly appreciate an instruction on how to get M1 environment ready for Glyphs scripting, an instruction that works.