I wonder if there is a guide to move from 6.22 to 7.0 lts
7.0 and 7.0 LTS are the same version; just upgrade your server like you normally would, but keep in mind that, like 6.x, 7.x will diverge into LTS and non-LTS until 8.0 is out, so you may want to switch now from the stable to the LTS channel, if you want to follow the LTS releases from now on.
Read carefully the release notes to make sure your system can handle the breaking changes.
7.0 is effectively “6.24” 
- there aren’t many breaking changes, although some of the more obscure command-line options were tidied up, and the minimum kernel version has been bumped - so if you are still on Ubuntu 22.04, install linux-generic-hwe-22.04 to get a newer kernel.
But really, all you need to do is change your repository settings to 7.0-lts and update.