Kinda remember if was installed with .1 iso it didn't upgrade the kernel automatically but if using the .2 iso it did. Not sure how yours were installed. I was at 5.x with my .1 install and did a .2 install to fix an issue and had the 6.x.
Some information here:
https://www.omgubuntu.co.uk/2023/08/ubuntu-22-04-linux-kernel-6-2
just a possible