This is a draft, will do a video soon’sish
Trying to work through the maze of wireless/mobile broadband is way to complex, after a few weeks work here is my thoughts.
You need to look at a sight like this to find out where to mount your antenna or moor your boat cellmapper
Then there are some background links that I found to be useful.
https://grouptestwinner.com/best-4g-lte-router Best DC Powered 4G and 5G Routers
https://youtu.be/S8ZZSdJJ27s How To Choose A 4G LTE Antenna
https://youtu.be/AqFD2b6yz-w How To Set Up a 4G LTE Antenna for Best Performance