Migrating iTunes Library to Apple Music: How long might it take?

Hi! I've just made the move from Mojave to Monterey, and I'm trying to migrate my iTunes library to Apple Music. I've followed these steps:

-opened Music holding down the Option key

-selected my old .itl file

-selected a location for my Music file to save

Then when Music opens, and I select Artists or Albums or Songs, I get a "Loading..." prompt and it sits there. I've let it go overnight and and it's still spinning. First I tried it with my original .itl file, which has many, many (many) playlists, mp3s (personal files on a local drive, not on the Cloud). Thinking it might be the amount of info that's making it take so long, I tried a different .itl file, one from my office computer, which is much, much (much) smaller. I still get "Loading..." and spinning, spinning, spinning.

Am I missing a step? Might it take this long? I just want to make sure the "Loading..." is common--or if it's a sign that I made a misstep along the way.

Thanks!