HDMI-CEC not working on rockchip64 Legacy
The OP also mentions reboot not working on Rockpro64, but that is a separate issue concerning only that board. I don't own it, so I cannot test.
On the other hand, I have tested the CEC issue in my Rockpi4, and the problem is there too.
Apparently, the issue had both:
A userspace component: Debian Buster’s libcec4 not supporting the Linux CEC API used by Rockchip driver. I uploaded a updated version of libcec4 to our repos (it should not give any trouble with any upstream change).
And also a kernel component:
DT not including the HDMI CEC pins for Rockpi-4b and RockPro64 (fixed both, it could be necessary to do the same for other boards).
I also modified the Kernel config to enable CONFIG_MEDIA_CEC_RC, just in case.