You have not really provided enough detail on the project, in particular you say ‘10ish km’ but no information on the environment. This is critical information, the difference in expected range between an urban area and good line of sight is more than 1000:1
I do sell a number of PCBs that allow very small LoRa receiver\transmitters to be built, basically just a little bit bigger than an Arduino Pro Mini, you will find the details here;
A LoRa device is by its nature a transceiver, so with suitable code can be a transmitter and receiver.
You mention that there are upward of a thousand receivers, which is rather a large and expensive project for a ‘true newbie’, perhaps you should employ the services of a professional engineer, mistakes in the design of the project could be expensive.