Spurious Double Clicks on Sequoia

I'd been having pretty serious problems under Sonoma, so I decided to roll the dice as an early adopter of Sequoia, risking the postgrade to 15.0.1. Sadly, I'm already regretting it. In particular, I'm having a rather serious problem with single clicks being frequently spuriously turned into double clicks.

I'm not able to reproduce the double click at will. It seems to happen only when I'm switching to a window after some time has passed. On the other hand, it's happening very frequently ... to the point where I'm really going to go crazy if I don't do something.

I've tried changing the double-click speed in the system settings. This hasn't had any effect.

I don't believe it's a hardware problem. First, I didn't have the problem under Sonoma. Second, it doesn't happen unless I'm switching windows after a delay.

1. Is there an easy way to backgrade from macOS Sequoia to macOS Sonoma?
2. Is there any standard way of blocking the operating system of allowing all double clicks? I can live without double clicks for a few months until Apple solves this problem (assuming they will solve it).
3. Are there any third-party utilities that can intercept double click events (and delete them, or turn them into single clicks or something else)?

PS:

Another aspect of this problem ... which is particularly disruptive. Many applications seem to respond to double click by resizing their windows in ways I'm not familiar with. I'm guessing this has something to do with Apple's newest attempt to implement window tiling features. Apple seems to have been struggling unsuccessfully to implement decent window manager features for a very long time, so it might make sense that the double click problem is related to an ineptly implemented tiling feature.

In practice, this means that when a window title bar is clicked, the window resizes in a way that requires me to manually resize the window again to get the old size back. (A second double click doesn't accomplish this.) Unfortunately, as near as I can tell, none of the new tiling functionality is very useful, and macOS seems to still be quite far behind Windows and Linux in this area. In any case, with the double click problem on top of this, macOS is more or less a basket case ... it would be really nice if I could reinstall a previous version of macOS, if that's possible.