Doodle Labs radios are pretty plug and play with the VOXL2, I've been working with that setup for a while. The breakout board used in that guide is one supplied by Doodle labs in an evaluation kit, but you don't really need it. The breakout board and radio shown in the pictures also seem to be older models, so the pinout and connections today are slightly different. The software setup is still the same, using voxl-configure-modem.
With the VOXL2, you just need this cable:
https://docs.modalai.com/cable-datasheets/#mcbl-00085
and an add on board that has a 10-pin USB + power port such as this:
https://docs.modalai.com/m0151/
Then just connect the 6 pin cable to the mini oem's power port (port 4), and the 4 pin cable with the twisted wires goes to the mini oem's USB port (port 1), the mcbl-00085 link has some drawings. Then on the VOXL just run the configuration script. Also the radio can get hot pretty quickly so be wary of that.
If you're using a mini oem for the GCS side you don't really need that breakout board from doodle labs, you just need a 5V 2-3A regulator to power the mini oem on port 4, and there is a Rj45 ethernet adapter from Ark Electronics that matches the pinout of the radio's ethernet port, and I like to connect it to the mini oem's ethernet port (port 2) for my GCS device to use, but you can also just use a USB-A to JST adapter connected to port 1 instead.