When I updated my old MBP to Catalina it was pretty ugly as well. There were a couple of points where I thought it was stalled, or it would reboot multiple time

When I updated my old MBP to Catalina it was pretty ugly as well. There were a couple of points where I thought it was stalled, or it would reboot multiple times back into the same exact screen and it seemed to be failing, but it did eventually succeed. I had to keep myself from messing with it.