Dusty I'm glad that installing from Windows worked out!
As I was flashing from Pixel 8 to 6a today, I noticed that when I'm in the WebUSB installer in Vanadium and I select 'Desktop site' in Vanadium's menu, the 'Reconnect device' button never appears during the flashing. It gets stuck, just as you described.
I wonder if that is the case on the Tablet as well.