neowin[.]net/news/remember-the-good-old-windows-movie-maker-you-can-now-download-it-on-windows-11/
archive[.]org/details/windows-movie-maker-6.0-setup
I was never a huge fan, but Movie Maker was quite popular until Microsoft killed it. Well, someone uploaded a copy of the Movie Maker setup file which is reported to work just fine in Win11. Note that since this is an unofficial source, take appropriate caution. Also, there may be security vulnerabilities in this older software.