Comment 12 for bug 1979244

This is happening because of phased updates. The libssl3 package was either manually installed, or it came preinstalled in an image, and now phased updates is preventing libssl-dev from being installed. There are two ways to get out of this stalemate:

1- Manually request the libssl-dev version to be installed: "apt install libssl-dev=3.0.2-0ubuntu1.4"
2- Disable phased updates, see the configuration options here: https://discourse.ubuntu.com/t/phased-updates-in-apt-in-21-04/20345