Its supposedly to learn typing habits. Heres how you turn it off.

https://www.privateinternetaccess.com/blog/microsoft-windows-10-keylogger-enabled-default-heres-disable/

It's pretty hard to prove what anyone is doing with closed source code.

Multiple. I understand that many of you won't believe or just don't know about Microsoft's spying, but that's the reality. It can happen that I can have wrong with certain things (I'm only human, remember that), but Microsoft spying on you is the fact of why I now using Linux as my main operating system since 2015/2016.

• Disable Keylogger in Windows 11 to Stop Microsoft from Collecting Your Data
• Where does Windows 10 save Keyboard input?
• Windows 11 Keylogger: How to Detect & Disable it
• From a ex-employee at Microsoft: You won't believe what happens when I turn off Windows 10 telemetry! - @Barnacules
• Microsoft's own privacy policy page (hit "Learn more" under "Personal data we collect" and scroll down to the bullet list for "Interactions")

There is a lot more proof out there, but I can't think straight to be able to find them. So if you want to dig some more, by all means, do it.