Consider using the Immich CLI (https://github.com/immich-app/CLI) for a bulk import. The UI might hang, not give you a reliable picture (pun intended) of which files succeeded and which files failed.

In addition to the mobile app which works like google photos and backs up photos you take automatically, you can also:

- Upload via the webUI

- Import a folder of photos on the host (copies photos to the Immich directory)

- Add a folder of photos on the host (leaves photos in place)

I didn't see the PlayStore link from their site. I do find it when searching manually.

Added.