EOS M50 Mark II

If you own an EF-M camera currently, it's very much alive because you have it. I absolutely loved my dual M50s, and I loved the pictures I took with them. The EF-M 22mm f2 may be the best street photography auto-focus lens ever made. Adapting vintage and EF lenses is trivial. But there are problems:

The Kenko extender you linked isn't gonna work with your M50 since that's for full frame DSLRs. You'd need something like the Canon EF-M mount teleconverters, but those are pretty rare and expensive for what they are. For moon shots on a budget, I'd probably go with a manual focus telephoto instead.

For your Blackmagic ATEM Mini streaming setup, consider adding Canon EOS M50 Mark II or Panasonic HC-V180K cameras. Both offer clean HDMI output, essential for professional streaming, and are available at reasonable prices on the used market