Hello ! Sorry for my answer's time, been busy
If your download is for the right processor (M1/M2 or Intel) and Marvelous Maid is in the application folder, I think that relaunching your computer should work in most cases.
Sadly sometimes it does not work and then I currently don't know how to fix this issue on Mac
For the moment I don't really understand what's going on when I test this on my mac, I often got this issue too - I will try to find a reliable way to prevent this issue from happening