Probably a bit more info than was asked in the thread title, but might be worth sharing what I've learned so far for future streamers.
There's some opportunity for income in live streaming but there's a significant cost barrier to overcome. I've done some research over the last six months and as Blake mentioned, Live-U is pretty much the way to go for bonded cellular. They've discontinued the Live-U solo, so the Pro is the only option it seems and right out of the box it's $1700. Then the data plan that accompanies it is easily $250 a month but it will provide the best signal between Verizon and AT&T which is essential to not drop video mid-stream.
Starlink is beginning to take hold though as either a supplement or replacement. It runs about $150 a month but there's some question as to the reliability when you're caught in the storm itself. Probably essential for streaming the northern plains and may end up being the primary data source in the future if not already.
As for the GPS, temp etc. overlays, I've been looking in to it because I would also really like to have this and haven't found anything on how it's done, and I'm not one to directly ask those who have figured it out already (figure they did the work so it's up to them whether they want to share it or not) so hopefully someone would be willing to share info on this. I use Streamlabs and somehow the data for the overlay is piped in but I just haven't figured out how to do it.
And to answer Warren's question, I stream with a Sony FDR-AX53 video camera mounted on the dash. There's definitely better quality cameras out there but it does a great job other than not handling darkness well, and it's somewhat reasonably priced. I'm currently contemplating adding additional cameras for rear/side views, as one camera just doesn't cut it anymore in providing a quality live stream.