When I was staying at DeSoto State Park, I met a couple that were traveling in a SpaceCraft 5th wheel, pulled by a heavy-duty truck. I was talking to them about their internet provider and they told me about Calyx Institute. I have done quite a bit of research on this and thought I would provide a little info here for people that might be interested in mobile high-speed internet.
Disclaimer: I have not yet received or tested the device, but I will update this thread to let everyone know my experience. I am not connected with Calyx Institute in any way.
So, the interesting thing about this organization (I don't call them a "company") is that they are a non-profit. If you make a donation, you will receive a WiFi hotspot device and a SIM that operates with the T-Mobile network "for free" for 12 months. In fact, the company I work for even made a matching contribution to them when I provided my receipt. They are based in New York as a registered charity. If you are interested in learning more about their charity work, check out their website: https://calyxinstitute.org/
I joined at the "sustainer" level, which will get me a 4G/5G Hotspot device and 1 year of service for a donation of $750. Subsequent years of service require a donation of $500. There are lower levels of membership that start at $500/$400.
They have been doing this since 2010, so I think they will be around for a while. You can do your own research about the organization - I haven't found anything negative about them or anything that suggests they are not 100% legitimate.