Ahoy there!
Some models with USB does indeed support Docker, but that’s generally not why it has a USB port. This port enables all sorts of other features (such as USB to Serial, additional WAN inputs, MAX Adaptors etc…).
You can view if a model supports docker under the Comparison Sheet online: Peplink.com - Model Comparison
Here you can also see that the B One & B One 5G does NOT support Docker.
Here example next to a BR2 Pro that does support,
Cheers!