Perhaps others have had this problem. Device is a nuvi 3590LMT. Trying to get it to update map, using Garmin Express version 7.28.0.0 on iMac running Sequoia 15.7.4
Garmin Express recognizes device, but according to the help videos, I should see either a "Map Detail" link or a "Manage Maps" button. Neither seems to be present.
See screenshot from my computer:

Any way to fix this?