I went from a portable 4G router, to my phone as a second SIM (huge battery hog), to a mains operated, because it doubled the theoretical speed due to enabling carrier aggregation and was the only way to reliably integrate it into pfSense which needs a persistent ethernet interface to boot.
The portable router would regularly lose the high-speed/frequency band, but the Three tower is many rows of houses away so likely gets deflected a lot. The mains operated keeps a solid lock almost all the time.
My thought is that if its going to have to run in NAT mode anyway, might as well use a unit that guarantees the best reception and speed. In my case, I still planned to yank out the mains operated router to take it with me on my weekends to Nottingham (which never happened thanks to pandemic).
