Despite many glowing reviews out there of the Raspberry Pi 400, there is a usability problem (in a daily-driver sort of way) that is getting little attention so far. In a nutshell:
“These issues (missed clicks, desync position vs clicks) could be explained if the OS was polling mouse input, rather than using buffered mouse input.”
Active threads on this:
https://www.raspberrypi.org/forums/viewtopic.php?f=140&t=291298
From your links, possibly a config fix for the mouse,
Oh, looks like indeed the Pi is polling for mouse by default. (lol)
Setting usbhid.mousepoll=0 in /boot/cmdline.txt fixes the issue.
I was not able to find a similar option to fix up keyboard. Does anyone know if there is a way to fix the keyboard buffering on the Pi400?
Keyboard unlikely to have one.
What I found with that one was that my keypresses had to be dead-center to register. I could fully depress the key from along the perimeter of the surface and not have it register.
cspan, How is the keyboard quality on the RPi 400? - Raspberry Pi Forums