There's plenty of tutorials but you can request a Google Takeout of your photos and then point immich-go at it. I can confirm that this works really well.
https://takeout.google.com/?pli=1 https://github.com/simulot/immich-go
https://takeout.google.com/?pli=1 https://github.com/simulot/immich-go
https://metadatafixer.com/learn/how-to-download-google-takeo...
I struggled with Immich, I didn't like the rclone option. I'm intending to go back to Immich but my first priority was to get the stuff out of Google. That's done, so with all my free time (ha!) I can get the family Immich going.