Reverting display accessibility settings in Sonoma

I made some changes to the default accessibility settings on an iMac running Sonoma and they did not work out. Not only do I have a screen with just black, red, and yellow blotches, but many of the controls for the accessibility features (check boxes, options) and the title bars of windows are apparently invisible or just missing. I would be happy to revert all the display settings back to their default but cannot find any way to to that. All the advice on the web I have found is to go into the Accessibility panel and change settings there, but as I have mentioned those controls are no longer visible. Short of reinstalling the operating system, any thing I can do, perhaps from inside Terminal, that would fix the problem? Many thanks in advance.