Synergy works on Ubuntu 21.04 and 22.04 LTS, however it requires you to login with Xorg instead of Wayland.
If you're using Ubuntu 22.04 LTS, you'll also need to use an older version of libssl.
To login with Xorg instead of Wayland:
1. Select the small cog on the bottom right corner at the login screen.
2. Choose “Ubuntu on Xorg” (see image below):
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