I just got a NanoPi Neo Plus2 for which I must prepare an image for our software. Basically I must have a working Ethernet-over-USB, Wifi and NIC.
I started with your current Debian image compiled with uses Armbian v8.75 and Linux kernel v4.19.20. In this image Wifi works, but loading the g_ether module does not seem to work. I assume I need to patch the kernel to make this happen, which means I need to build my own images.
So I created a Virtualbox environment as described in the documentation, and compiled an image with all the defaults (apart from a date-tag I add to the kernel name for identification). I installed the image to the eMMC and booted. In this image there is no wifi interface and g_ether also does not work. The armbianmonitor output for my new image is attached to this query (http://ix.io/1H9v), but I also created an armbianmonitor output for your Debian image (http://ix.io/1H9u) in which the Wifi interface does appear.
Wifi: Comparing the dmesg output, it is obvious that firmware fails to load into the AP6212 wifi unit on my image. I've downloaded and installed firmware from several sites (official and other) to try and fix, but nothing solves the problem. Any ideas? Is this a regression in the Linux kernel (4.19.20 -> 4.19.36)?
OTG: Configuration of the USB-OTG for the Ethernet-over-USB gadget is usually done in the DTS files on ARM processors (I think - a bit rusted). I've noticed that there are several patches applied to the kernel from other boards such as the OrangePi, so maybe someone already has a patch for another H5 based board which will work for the NanoPiNeo+2?