The only difference appears after 6 months after release - if you don't want to upgrade (you should) you have to find vendor that will sell you support for given release.
E.g. Azul provides it for 11, 13, 15, 17. Oracle for 11 and 17.
Adoptium provides builds (not LTS) from 11 and 17 branches, where some vendors push their bugfixes. So it is like a semi-LTS, they won't fix your bugs, but if someone fixed a bug it most likely will end up on that branch.