Per Radxa here, it is possible to obtain CPU temperature via "sudo cat /sys/class/thermal/thermal_zone0/temp".
But the following paths do not exist on Armbian 23.05.1 Bookworm with Linux 6.1.30-rockchip64:
/etc/armbianmonitor/datasources/soctemp
/sys/devices/virtual/thermal/thermal_zone0/temp
Running armbianmonitor -M, also does not show the temp:
Time CPU load %cpu %sys %usr %nice %io %irq C.St.
22:29:52 408 MHz 0.02 0% 0% 0% 0% 0% 0% 0/6