You could try disabling what you can through Settings, Apps. I have a disabler and have it turned off completely, may be an option depending on how bad it is. Have you reported back to the beta folks about the issues? They may have an option, but that's what beta testing is.
Wish there was an uninstall updates option or something.
I use BKDisabler Pro, at third party app. I would imagine, if you uninstalled all the app updates there were recently done to support Bixby, then that would disable the beta. But that might do other stuff![]()
I'm still signed up for the preview so it'll just load again.