Connection of OpenWRT device non-facing the Internet to AWS server

Hi there,
I am in a bit of a pickle.

I have a Ubiquiti Bullet M2HP and a AC Dual Band that I am using to monitor the area around my lab for Radio Frequencies. Both have the OpenWRT flashed in. I have associated to them a Static IP and I can connect to them via SSH, they both work and I can see them once they are connected to my computer via Ethernet Port and they are powered via PoE.

I am now trying a new thing. I would like to connect them to the Internet Provider Router via Ethernet port and I would like to pipe/transfer the data that I am collecting to my AWS Cloud Server. The devices are non internet-facing devices clearly, and I would like to understand what's the best way to connect them to it without having to build a "Sync Module" that connects to the Internet for them and then transfer the data to the AWS server. Should I use the OpenVPN? Can I flash it into the flash of the M2hp and AC? Am I completely off?

Any help is very much appreciated!

Only option across self-inflicted air-gap:

What about Creating a MQTT connection with AWS IoT Core by installing python on the Devices and summoning a program to provide the connection between them?
@ercolino what do you think?