E.g. Ubuntu 22.04 Linux kernel 5.15.0-203.213 was published in Canonical's proposed kernel PPA on October 26, 2026. So just enable Canonical's proposed repository, use APT pinning to prevent automatic installation of untested packages and install the patched kernel. I agree that they need to get quicker at pushing these updates into stable, but it's not as if you don't have a choice.