I've had 1 success out of many attempts at using do-release-upgrade. However on Debian I've never had a single failure at using apt manually for version upgrades. Can Ubuntu be updated the same way by editing the sources.list and apt update apt upgrade apt full-upgrade?

I know it isn't their supported way. Just seems the supported way is nothing but a waste of time as like I said, I've only seen it work once out of many upgrades. I usually end up fresh installing after that due to various problems that I can't seem to track down.

I've used
it uses a smart upgrade where it does the important system packages first and handles any conflicts and also gives a report about what needs to be done next.

found this...here

I've done the 18.10 > 19.4 update on my desktop (do release-upgrade) and two Dell XPS laptops (change apt sources manually). No problems with any of them.

The only time I had problems with "do release-upgrade" was during a pre-release (may have been pre-beta) phase for an earlier release...may have been 16.10.