I ran into the same problem after following the pine64 wiki and downloading the latest build from November 2022.
In case anyone runs into this problem in between releases, I was able to get network support by building the latest pine64so configuration using the latest kernel option.
Follow the build steps in the readme https://github.com/armbian/build#simply-start-with-the-build-script
It takes a long time to build, but it "just worked" once I reimaged the SD card with the output ISO image. Just make sure that in the configuration menu you choose the pine64so board and pick the latest or edge linux kernel to build; I think the driver will be in kernel version 6.2.
Maybe about 20 or 30 minutes into the build, I could see evidence that it would work because I saw drivers/net/phy/motorcomm.o in the log output. The driver file is recently added to the linux kernel https://github.com/torvalds/linux/blob/master/drivers/net/phy/motorcomm.c
The message of the day displays, "Welcome to Armbian 23.05.0-trunk Jammy with bleeding edge Linux 6.2.10-sunxi64."
