In your opinion, which canon APS-C dslr has the absolute best autofocus and frames per second for basic wildlife photography?

I’m wanting to get into some basic and barebones wildlife photography, something I can have fun with while going on walks in local nature preserves and state parks. I’ve already decided on the Sigma 150-600mm contemporary lens. I just need an apsc body, as all I have currently is a full frame 6D(original MK I, laughable autofocus performance aside from the single center point) and an old 20D. I know the “standard” is the 7D mk ii, but is there any better? Budget is around $300-500 for the body. So mirrorless is out of the question. Which has the best autofocus out of the whole line?