It's been a while since I've played, but I suspect you've got a lot of choices. I shot a 686 (L-frame) and used a Ready-Tac, Comp-Tac, BladeTech, and finally, a custom one, made by a local guy.
I thought the BladeTech was too high, i.e. the top went all the way across the top of the cylinder. A little work with the dremel fixed that.
My Comp-Tac is a great holster, but at the time, they didn't make a k-frame holster. I don't think they make any revolver holster now. Too bad.
I really liked my Ready-Tac, and can certainly recommend it. I would've kept using it had I not had the custom holster made.
https://cpwsa.com/products/ready-tactical-s-w-revolver-holster?variant=413588833
Great to see another wheelgunner shoot IDPA. If you've got questions, feel free to ask.
EDIT: Now that I think of it, I have shot my M66 in IDPA before, so I have a kydex IDPA-legal k-frame holster. It's not fancy, but if you want to simply check out IDPA without having to buy your own holster, I'd be happy to loan it to you until you decide it's something you want to stick with.