Are you able to ring them and have them authenticate your devices login? I don’t see why this wouldn’t work - Are you using MDM to manage the device centrally? You could try Bluemail if you’re on Android (it sounds like you are) sign in to your gmail business account and try use the magic email link there.
Unfortunately you can’t seem to “open with” outside of a work profile like you can with “share” (see below, you can simply tap “switch to personal profile”)