I had the exact issue. After rebooting my computer, my mouse and keyboard were completely unresponsive and I noticed that a blinking cursor on one of my start-up programs became and stayed solid, suggesting that my entire system had crashed.
I'm not sure if you're still having the issue, but I was able to solve my issue by reinstalling input devices:
Hey there I wondered the same thing! and I hope that this starts to be something that makes it into the system settings some day. The reason being: that once you have set it up, it is out of the way and you don't think about it ever again.
I have used a different option that is a more straight forward slider that you can drag and set the speed.
I used ...
This solution worked for me so far:
Edit /etc/bluetooth/input.conf and under section [General], uncomment the line IdleTimeout=0
# Set idle timeout (in minutes) before the connection will
# be disconnect (defaults to 0 for no timeout)
Interesting that defaults to 0... but in my computer bluetooth was disconnected after roughly 10 minutes.