Ubuntu 20.04 is the first version where BT worked decently for my machines. I don't know if bluez fixes have been backported to 18.04 (but I don't think so), so

Ubuntu 20.04 is the first version where BT worked decently for my machines. I don't know if bluez fixes have been backported to 18.04 (but I don't think so), so if you use BT, the upgrade (to 20.04+) may make your devices work better. For people with modern AMD machines (which is not your case), 20.04 should be a significant difference, since kernel versions around 5.10 added support for recent AMD CPUs. The two above are the only things I remember making a difference on my system. Software wise, it depends on the user practices. There are a variety of ways to obtain up to date packaged software (docker images, application images, PPAs etc - often from the official maintainers), so one can stay on a relatively old Ubuntu version, and still have up to date software without manually compiling anything. The exception is the kernel.