I wiped off my Windows 10 installation today. It wasn’t because of the intrusive telemetry or the ads in the start menu but desktop composition. It adds some slight but noticeable latency that makes typing feel uncomfortable. In Windows 7 you can turn it off.
If you’re fine with unresponsive UI operations and graphical tearing, then, sure, go back to Windows 7 or earlier and turn off compositing to get a few ms back when typing.