My Apple Studio Display firmware update won't finish downloading

When I try to update my Apple Studio Display, I get a "My Apple Studio Display firmware update could not be completed" message and it stops at then of what appears to be a full download of the update--except there's nothing in Downloads.

The monitor is connected to a new M4 Mac Mini (M4 chip, 8 core, 24 GB unified memory, Sequoia 15.1.1 OS, serial #DVH2NJ0NP6), and everything works fine otherwise. I have 100 mbps internet via a fiber optic line and an ethernet cable connection. I start the update through Software Update and get an indication that the full 729 MB download has occurred, but then the error message comes up and no download appears anywhere on the unit.

Any suggestions, anyone?