Boosting any cellular signal is going to have pros and cons given how that is done, and in most of my testing / customer use, it is not as effective as really high quality antennas paired with purpose-built LTE routers.
You might want to check out the Peplink HD1/HD2 domes. I did an article and a video on them:
Peplink MAX HD1 Dome
It is an outdoor dome with the LTE radios directly inside the dome. The SIM cards can be inserted into the dome itself, or you can both power the dome and manage the SIM cards in an inside product called a SIM injector.
I have two of them aboard my boat and they have outperformed even high end LTE antennas and $10k LTE routers in almost all cases. There are a bunch of caveats (article forthcoming on using multiple domes) but in general this is the direction I see a lot of vendors moving - LTE radios outside instead of lots of cables and complications.
They're not cheap, but if you are really wanting reliable connectivity with a minimal amount of cables and loss, this is a good option.