Wireless Joint

Current setup - T-Mo Magenta Max with a Sim in a Gl.iNet gl-x750 with TTL edited to enable unlimited data. I also have an ATT business plan with a sim in a Inseego 8000 hotspot.

This is working pretty well for me as I travel the country in an RV. Typically if one provider is slow the other is pretty good. BUT, I'm wondering what I can improve. Is there a mobile router with better modems than the gl.inet? Should I consider better antennas? What about the TTL edit for T-Mobile, as I understand it, the gl.inet work so well because they come back as a generic android device, which can bypass data caps.

Basically, is what I have the best for what I'm looking for? I don't want to spend thousands of dollars on this.

With cellular modems you will get what you pay for really. BUT you can upgrade without totally breaking the bank. The Cudy LT18 is a big upgrade but it can't tether the 8000 hotspot.
https://thewirelesshaven.com/lt18

You could get a NEXS2GO and like an Quectel EM160 and use your Tmobile SIM. TTL and all that is in the firmware, openWRT based like the glinet.

https://thewirelesshaven.com/shop/route ... go-bundle/

Antennas will depend on each location. I consider them as tools that are needed for different scenarios. I am not a fan of the all in one omni-directional "RV" antennas. I think they are overpriced marketing at its finest. They "work" I guess, but if you are going to pay for an outdoor antenna upgrade, I'd get a directional set or a large omni-directional that can actually do some work up there. Not a 2" tall dome that sits flush on the roof with 7+ antennas stuffed inside a 5" round housing. My opinion.