I use Distrobox with my NixOS machine for when I need AppImage support (or some random binary that isn't equipped for Nix's weird ass directory layout) and it's amazing! Pretty much native speed, and when I'm done with it I can just wipe it out. Perfect!
I'm aware, but the appimage I run (Slippi Launcher) will run other appimages, and appimage-run can't handle that, since it extracts the appimage, then runs the contents, but it won't automatically do that for other appimages that are run.
Which is why I used a Distrobox and it was awesome, worked like a charm. I used Arch previously, and I just made an Arch distrobox and it worked perfectly.