'Winapps' and 'winboat' on Linux allow a windows image to run in a Linux docker container and permit just the app to be streamed to the Linux desktop (after initial setup). I haven't played with it yet..but you could theoretically set up a windows host on a different remote server via tailscale or netbird and have them RDP into the windows docker container remotely.

Unfortunately my parents run macos and these tools are not meant for Macos. But like you said there are apps like UTM that provide a nice shell for QEMU on macos. Not as nice as streaming just the app, but a good start. These work great on new macmini with apple silicon.