Kernel 5.15.0-73-generic is the default kernel on 22.04 at this point. The reason why it has remained the same is because you had the hwe kernel installed on your 20.04 release instead of the default one.
What you can do on 22.04 is install the hwe kernel again so that you can use kernel 5.19.0-43 at this point.
sudo apt install linux-generic-hwe-22.04
The new installation will not remove the current kernel. In case of problems with the new kernel, which is highly unlikely, you can always use the grub boot menu and tell the system to use the current kernel instead of the newly installed one.
On this link: How to get to the GRUB menu at boot-time? you will find instructions on how to activate this menu.
If this happens though, you have to remove the hwe kernel afterwards so that you don't have to select through the grub boot menu the older kernel every time you start your system.
sudo apt purge linux-generic-hwe-22.04
Personal recommendation:
If your system is running well with kernel 5.15.0-73-generic, I would recommend you keep using it instead of updating it. The hwe kernel is exactly what it says. It's a Hardware Enablement kernel that doesn't have to be used if the system is running OK. The default kernel is receiving all the necessary updates regularly and you don't have to worry about installing a later kernel manually.
