Universal Control stopped working
The control between iMac (2021) and MacBook Pro (2021) stopped working this morning. They are both on the most current version of Ventura 13.4.
After reviewing a similar thread here (I had to start this new one as the other thread is closed for comments), I turned on/off universal control on both Macs as well as restarted them. That did not fix the problem.
What did fix the problem was when I added and deleted each Mac on other Mac's display settings (mirror or extend to). That triggered the "Link Keyboard and Mouse to" connection, the Universal Control.
Hope this is helpful if you are facing this problem.
MacBook Pro (2021)