I did a reboot from 8081 and upon reboot it completed initialization and booted fine. Just sharing in case this is useful for someone.
I have three hubs, 1-3. Hubs 1 have lots of devices, Hub 2 has a few.
Hub 3 has only 3 devices but participate with those into hub mesh, sharing these local devices with hub 1.
The hub that hung was hub 3. Surprised me as its the least used hub with almost zero automations. When it rebooted i got the exclamation mark under the status button and the text "zigbee unavailable". Not sure if this is related or not (and i could be misremembering the message, it was about zigbee that i remember). I have no zigbee devices on hub 3.
After a minute or so that message disappeared.
I rebooted one more time about ten minutes later, once that reboot completed i logged in and there was no zigbee message after that reboot.
I'm sharing in case it benefits someone. right now the hub works well. I didn't have to downgrade.