Does anyone have an opinion about whether I should buy a) used Canon EOS R, b) used Sony A7sii, or c) new Canon EOS RP?

For context: I mostly intend to shoot/edit/make marketing material for bands and theater (in 1000 years when that shit is allowed again) and music videos. And either way will be purchasing a Tamron or Sigma 2.8 24-70 as my main lens, and *hopefully* a 2.8 70-200 as secondary.

If somehow I have enough extra money, would additionally either get a set of primes (say, a <2.8 aperture wide angle and a nifty fifty type lens and maybe an 85 or 100 or 135) or a 14-24 2.8.

One last piece of information: slightly leaning Canon because a) my dad will still be running Canon cameras + lenses and I'm sure we'll end up shooting things together and b) I want to up my color grading skills and I'm interested in C-log for that reason.

Finally, a poll:

also price/value-wise EOS R is the most expensive at ~$1400-1600 used, A7sii is second at ~1100-1300 used, and RP is the cheapest at $1000 used. But tbh the price difference is not large enough to reaaaaaaaally justify buying an extra lens and a cheaper camera so.

*RP is $1000 new, rather.