I think the easiest would be to downgrade to the 350mbps plan and see if you can even tell there is a difference. If you do a lot of downloading of large files (Linux isos and steam games) those will go slower. Anecdotally, I’m a software developer who works from home and I have never felt an upgrade from my 300mpbs plan to be necessary, but I don’t download a ton of large files very often and this decision obviously takes into account my personal income and expenses.
They are receive only devices that work using radio signal. Messages are sent using a transmitter of some type. I understand this is a very basic description, I’m not an expert, just have an interest in telecommunications related things.