The three adapters are easy to understand.
1. The cheapest simply allows you to use your EF and EFS lenses.
2. The next level also gives you a control ring that you can program to do a number of functions.
3. The last one allows you to drop in various filters at the adapter itself. Very expensive but gives you the ability to add filters to lenses that cannot add filters.
#1 is the one you probably would go with first.
Bottom of this page goes through the 3 adapters: https://www.canon.com.cy/mount-adapters-ef-eos-r/
You know Charles, you aren't that far from me, less than an hour. If you are near the Fort Wayne area, let me know, and I will meet up and let you borrow the M50 for a week or so. I have a 15-45 lens, and I have the EF/EFS adapter you can try with your lenses. I am always letting people borrow my equipment. My sigma has been borrowed a few times for an eagle outing, my TC, etc. We also go to Kendalville quite often to visit Rural King, and to eat at Long John Silvers (not sure why my wife likes that place, but it makes her happy).
This would definitely give you an idea of whether you want a mirrorless system right now or not, or to try to find an 80D deal or 90D, at no cost to you other than travel time. 