Antenna gain isn't everything: I've set up the LTE6 for people, and in some cases I was able to get more speed in the same location with the latest iPhone.

In locations where you're at the edge of coverage, and your phone is not getting anything at all, it's great.

I sometimes suspected that the modem in these LTE / 5G routers is less well tuned and tested with various network than what you have e.g. in an iPhone.

This is my experience as well. Unless you actually need a directional antenna, an iPhone will be faster and more reliable than dedicated hardware.