I expect 23.05 branch to stay on kernel 5.15 for its lifetime. 5.15 is scheduled to get LTS support until October 2026.
5.16 is not a kernel with LTS support. Support for kernel 5.16 already ended in April 2022.
The next LTS kernel following 5.15 is 6.1, that is already used in master branch.
If someone likes to backport support for newer hardware to 23.05, it could be done. But not by a bump to higher kernel versions that are already out of support.