I cannot give you a definitive answer, but I would put my money on the RP, despite it being a cheap full frame that hasn't had an update for a while. Shooting in servo mode, doing street candids? The eye AF works well for me and the RP, and the amount of images I shoot with moving subjects that have perfect focus of the eye is amazing, more than I could ask for, really. The only thing I desire at this point is faster FPS shooting, which at present (in the RP) seems faster than even my Sony RX1Rm2, which is a fairly high-end street camera that is a few years older.
I mainly shoot full frame only, but I have shot with M's as recent as m6. ( I have had m3, m5, and m6.) They were not great for AF at all, and I just cannot imagine the cheap m50 vlog camera being much better (for stills). I think I would prefer 5dm2 Live View over a M anything, but that is likely just me and my full frame prejudice.
Where I would say that an RP would work fairly well in many pro situations, the m50 isn't even close. I would even venture to say that in many cases, the larger sensor of full frame is almost always going to give better AF when all other parameters are similar.
Just take what I say with many grains of salt. It could be that I cannot see past my sensor size hate.