It was Canon's first foray into a “professional” camera body for sports shooters, photojournalists and the like.
seriously? Previous 1-series cameras beg to differ.
As for the R3 (and future R3 mkII) vs the competition, not really seeing anything interesting from Sony or Nikon.
A9 mkIII has global shutter, yes, but at the cost of DR and a ridiculous pricetag for what isn't even supposed to be their top dog. If you need high flash sync speed and have some very quick strobes, good on you. You should already be using something with a leaf shutter though. Price difference vs a Hasselblad X2D is small but the difference in image quality will be huge.
Nikon Z9 is somewhat meh, good option but nothing special, expecting similarly for the Z9 mkII. It's a bit like the D6 vs the 1Dx mkIII. Or it wuold have been if the R3 hadn't had eye-controlled AF.