6.6.6 would be a patch release to 6.6 and Linus almost never bothers with those. It'll be more the territory of Greg Kroah-Hartman.

6.5, 6.6, 6.7 will be major versions of the kernel. All of them will receive patch releases (6.5.1, 6.6.6, 6.7.2, etc); one of them may become LTS, they may not. Whether gkh decides to skip 6.6.6 and go to 6.6.7 instead, that's up to him, but it'd probably cause more issues with scripts than it'd be worth it. I get that people can be superstitious, but imo it's not worth it.