On my side I've been running 5.16.11 from linux-image-edge-rockchip64_22.02.1 and it has been rather stable, with occasional (once every 2 months?) lockups. I'm running on a jammy base.
Just saw that the 6.6.2 kernel is available in the test repos, anyone gave it a try?
armbian-bsp-cli-helios64/jammy 23.11.1 arm64 [upgradable from: 22.02.1]
armbian-firmware/jammy,jammy,jammy 23.11.1 all [upgradable from: 22.05.1]
linux-dtb-edge-rockchip64/jammy 23.11.1 arm64 [upgradable from: 22.02.1]
linux-headers-edge-rockchip64/jammy 23.11.1 arm64 [upgradable from: 22.02.1]
linux-image-edge-rockchip64/jammy 23.11.1 arm64 [upgradable from: 22.02.1]