I just bought a GX9 5 years after selling my whole system cause I missed the form factor so much. M43 really is the best compromise between size and image quality imo, with the caveat that I'm not a professional. No other mount lets me casually EDC an 80-300 equivalent lens.

There's Esquisse (https://esquisse.camera/) trying to step up, but it's still in the very early stages.