There’s a lot of general UI improvements, even if it’s not as good as Catalina. Feels more responsive, which is an opinion I see a lot more on lower end hardware too. No improvements in GPU performance though, just UI.
Most of the new features are still present on Intel. I can still do things like plug-in my laptop and use my Mac Pro display. Improvements to control center, Bluetooth, UI improvements to System Preferneces.
But like I said, no big improvements to Metal performance and at this point you’re going to risk stability of your tools.
Oh, and if you have a variable refresh rate display, Monterey will support it on Intel as well.