Migration and exports should definitely be transferring login names and keywords as well as passwords.
If this isn't happening for you, I would definitely like to investigate what's happening here.
For starters, would it be possible for you to create a test user in Master Password with some logins and keywords assigned, to see if it migrates correctly? If not, it would be very helpful to have some screenshots and your test user's Master Password export file, so I can investigate the details.
You may also contact firstname.lastname@example.org or https://support.spectre.app for more personal private support with your own user if a test user is not able to reproduce the issues you're experiencing.
Let me know how it goes!