I’ll quickly provide JammyUpgrades - Community Help Wiki
If you contrast the upgrade instructions for 24.04 you’ll find no reference to 20.04; as the jump from 20.04 to 24.04 isn’t supported as already stated.
I’d also read the release notes of Ubuntu 22.04 LTS or the release you’re going to, any problems encountered during Quality Assurance testing tend to get mentioned there (with mitigation pointers) too. These can give a clue as to how smooth or what potential problems you could run into, if you consider your actual install(s). as you scan the document (upgrades work at package level)