To add a data point, I upgraded Ubuntu from 19.10 to 20.04 a week ago. It was 99% uneventful maybe for the first time in 10 years. I didn't have to reconfigure even the dozen Gnome Shell extensions I use. The missing 1% is the new openssl. It didn't let me connect to a few servers with old ciphers. I had to google how to enable them again. Hardly Ubuntu's fault and I don't have control on those servers or I would have upgraded them too and solved the problem in the right way.
