Try connecting keyboard and display and see what happens. My Umbrel was sometimes getting in a weird state and it would get stuck after restart. Keyboard stops responding on linux login prompt.

As far as I can tell the reason for this was that the power supply I got with RPi can't handle both RPi and the SSD... so now I'm powering it with power brick from Pixel 6 and that seems to work well (that one gives between 15 and 30 watts)