How One Find Modem Specs?

Make and Model are Broadmobi BM818 (no need for any tricky commands because they are the same for everyone)

That just leaves the variant unknown.

You could either take a punt that the variant you have is -A1 (for North America) or check it, with greater hassle, using: https://source.puri.sm/Librem5/community-wiki/-/wikis/Tips%20&%20Tricks#executing-an-at-command-on-the-modem