I use a script (python, since it's required for my job so it's not suspicious to be using it) that alternately clicks on the IDLE window and the Teams window every 10s or so, basically flipping focus back and forth. This keeps my status green / Online in a way that hopefully is at least a little less suspicious / easily caught than repeated identical keystrokes.

I also use SetThreadExecutionState from kernel32 to make sure my machine never goes to sleep. The intended purpose for this is for e.g. video player apps as a way to tell the system, "Hey, the user is watching a movie, so even though no input is happening, don't go to sleep", but you can basically have a cmd prompt report itself as the same thing. The venerable pinvoke.net has everything you need to do the same thing in Powershell. ;)