I've got it running the xfce4 desktop at 1.70Ghz(cpu1-4) and 2.02Ghz(cpu5-6) plus a few other tweaks. With kernel 5.9.9 the issues with eth0 seems to have gone, although there were a few times it disconnected/reconnected on its own.
Now that 5.10 final is released, waiting for Armbian