While I don't know for sure if this is the issue, but it could be that if something changed in the updated driver from AMD that, Saphire will also need to update Trixx. You might see it there is a newer version of Trixx available. If not I would ask Saphire support if they have any idea why the new driver might be making the feature not work.
You of course can also report the issue to AMD: https://www.amd.com/en/support/contact-email-form
FYI, it is pretty common that a change if a new driver does not install properly or that old data does not get uninstalled.
Espeically if you have a Windows 10 feature called "Fast Startup" enabled, which it is by default. You can disable it, just google how. This feature has the habit of cacheing old driver data conflicting with new installs.
I would try and disable Fast Startup.
Then download DDU from wagnardsoft dot com. Follow the included instructions. This will give a clean slate for installing the driver again.
Then with the Internet disabled re-install the latest driver.
If it ends up being you need to return to the last driver to get the RGB to function. Run DDU again and install the driver that used to work.