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:
You can install custom cursor themes in your profile using the following guide. You can find other themes that will work but for this example I am using the Obsidian Left theme.
Download the theme archive from here.
If it does not already exist create a directory named .icons in your home folder, from the terminal you can run:
Unzip the ...
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.