Unfortunately, it's not all good news.
Whilst the screensaver works the legacy screen saver process (legacyscreensaverx86_64) it appears to use to run does not quit when the screensaver quits and eats memory/runs the CPU at high level burning battery.
The only way to stop it is to force quit it in the Activity Monitor app.
https://www.reddit.com/r/MacOSBeta/c...and_using_100/
I'm going to have to stop using it for now (first time since release!) but will check regularly to see if it gets fixed.