I am confused as well by getting a clue what you are trying to do
Kernel and userspace are independent in Armbian. You can use any userspace (Ubuntu Jammy, Noble, Resolute, Debian Bookworm, Trixie, Forky, Sid) with any kernel package. Latter is always the same.
Rockchip RK3588 is a bit special in terms of kernel versions. Let me give you brief overview.
6.1.y is a based on Rockchip BSP kernel which is close to feature-complete but a bit outdated.
6.12.y which is currently our current branch and was the latest mainline LTS kernel until a few days ago. However at the time this was released a bare minimum of drivers were merged into this version
6.18.y (or soon 6.19-rcX) is edge and has a lot more hw features merged into but still isn't feature-complete. Collabora is working on that like crazy.
Userspace upgrades are neither tested nor supported by Armbian. Not because we don't want but because we don't have resources to test all kinds of scenarios for dist-upgrades.