How do SMS text messages work?

Problem: on the peplink max br1 mini, under SIM Toolkit it only says “No SMS”.
If I place the same SIM in a jetpack and send it a test text message, that SIM in jetpack can receive SMS messages at the same location. If I put the SIM back in the BR1 mini and continue to send it test text messages from another device, SIM Toolkit still says “No SMS”.

Question: I have better antennas on the BR1 mini than the jetpack obviously. For data, the BR1 can usually get three to four x the data speed of the jetpack. The BR1 almost always connects on 700 mhz.

Is there something about the way SMS are sent vs. Data that might favor the weaker antennas of the jetpack?

My thought yesterday is that it is a software issue or setting on the BR1 to enable SMS messages through the SIM toolkit that I’m missing.

I’m wondering if there is something about the antennas, frequencies that it connects on, etc. that might be allowing a phone or jetpack to get a text message and not allowing the BR1 to receive it. (i.e. are they sent over the same frequency and data stream as the data connection, or might some older tower send a text message on a different frequency only, or something I’m not even thinking of?) This is regarding verizon.

Anyone have a good primer for how text messages work and how a text message transmission differs from LTE data connection?

I was expecting that if I could get at least 5 mbps LTE data (700 mhz), text messages should come through fine too. However, maybe this is not the case?
Is it possible that an antenna may be strong for LTE data and bad for getting a text message through? Or should they both come through on the same frequency from the tower?
Is there greater error correction in the LTE data stream but maybe different or none for a text message so it might not be coming through because of corruption?
Are there other physical factors that would make a text not come through to a device while it has a fine LTE data connection?