You can try as you want but the OS is just not good enough. And there’s plenty of people complaining about the UI performance. I have many Macs and it’s the same. The M1 Macs are just a little bit better in this aspect.What does your CPU usage and memory pressure in Activity Monitor look like when you're getting lag? Also, any chance you've got a USB-C dongle connected with an ethernet port? One of the more common Realtek ethernet chipsets found on dongles is missing a hardware-accelerated driver for macOS, meaning it can take up a lot of spare CPU cycles.
Given that this is the first time I've ever seen complaints about UI lag on an M1 Mac (and I know several people who own one, and use one myself), this sounds like either a hardware defect or usage issue rather than a universal problem with the OS. Even at 120 Hz, I've never seen my M1 Pro 14" stutter or drop a frame. Hopefully with some troubleshooting your machines can run similarly smooth!
And using your Mac at the native resolution is a different thing. I’m using my Mac mini with the 27” 4K LG monitor and macOS is making some mumbo jumbo with the scalling and as a result it renders much higher resolution than it needs to to properly render the UI. You don’t have this problem in Windows because it handles this in a much better way. And that’s why even a decade old PC is much smoother. macOS is just not good with external monitors, especially if you don’t use a specific kind of monitors. I can’t understand why is it such a big problem for Apple to improve this. They just don’t want to I think.