My primary is the mofi4500 and it's a good router, just picked up an Orbi LTE router for traveling around (with external antenna https://www.amazon.com/gp/product/B088FBV6HF). It works with the at&t sim but it's not as configurable as the mofi. I'll keep them both for the same reasons, I need Internet to work.
Put in the tmo sim today, so far so good... but it's still early. I used about 700G last month on at&t, this plan is supposed to be 900G so I should be okay.
So currently I use this antenna from Amazon with the bandpass filter that blocks DC-790 mhz with a pass through from 790-890 MHz and blocked from 890 up. That made a bigger difference than the antenna did as it allows you to utilize the gain in SDRTrunk cleanly. https://www.amazon.com/dp/B088FBV6HF/ref=cm_sw_r_cp_api_glt_fabc_6M156NTZFRQ678D4XNX6?_encoding=UTF8&psc=1
If you’re in a city center I recommend at least blocking out FM, possibly AM and FM as well with these.
Broadcast AM Reject High Pass Filter (2.6 MHz HPF) by RTL-SDR Blog https://www.amazon.com/dp/B01N9SHS7P/ref=cm_sw_r_cp_api_glt_fabc_GGT93BTYWQ7R16XJBWTS
Broadcast FM Block Filter (88 - 108 MHz Block) by RTL-SDR Blog https://www.amazon.com/dp/B01LE9LRPM/ref=cm_sw_r_cp_api_glt_fabc_ZCK0NZTN2KM2BN81H9TH?_encoding=UTF8&psc=1
I do not have experience with this LNA but it could also be of use if you’re still having issues with using filters and a better antenna
RTL-SDR Blog Wideband Low Noise Amplifier Bias Tee Powered https://www.amazon.com/dp/B07G14Q6XX/ref=cm_sw_r_cp_api_glt_fabc_QRM87ZYE8JPT16XMDT66?_encoding=UTF8&psc=1
Good luck and let us know how it goes!
What do you think about this antenna? https://www.amazon.com/10-12dBi-External-Bracket-Booster-Nighthawk/dp/B088FBV6HF/ref=psdc_3015438011_t1_B074YWTCB1
Is it compatible with helium? But antenna conector is SMA Male. Thank you.