Peaches and Dulcinea: T-mobile Gateway (any gateway, help)

To fit 10-billion phones through a single gateway would be impossible, I get it, but read this (It's in greek, sorry about that)
The T-Mobile gateways do have a DHCP server which is set with the fixed gateway IP of 192.168.12.1 and the network mask of /24 for the Class C, IP network. The DHCP scope appears to be from 101-254 and the gateway address is excluded. Some users do connect an additional wireless router and double NAT just to have additional local network controls and features. Devices that do connect to the wireless or Ethernet network directly via the available gateway resource are restricted to the 192.168.12.X/24 network. There are workarounds for ways of communicating across the 464XLAT environment but of course it all comes with a cost.
When I directly quote someone the rest of my page is ruined by teeny multicolored fonts....
Anyway I don't know why but the guy is just wrong.
Wait, define "Gateway."
My phone has one that it hands out to anyone who asks for it, and my router is happy to tell me what it is (I didn't know for the last blog-entry I erased, now I do)
To set up DHCP you need to know the "Default Gateway," assuming it isn't seasonal or a temporary construction site, or even some hacker.
There can be (should be) only one DHCP server on a home network, uhm,
But unless my phone is on WAN (the company-side, the internet side) it won't dispense any DHCP info (so it's not like you can say,
"The Manager is sick, get what you want from room #3"

Putting info in manually is perilous too (witness the temporary construction-site above, that they put up on Tuesdays and at Christmas)

I could just *tell* you what my damn-gateway is, but what if it's for criminals or subscribers being investigated?
I would maybe wait until Someone at google has a result (My gateway address is unique, I am alone amongst Billllions, so far)

But I see the problem, maybe:

The physical device others might call a modem is known in t-mobile parlance as a "gateway" and I had the link a second ago...It's a box, with little lights.

https://www.t-mobile.com/support/home-internet/askey-lte-gateway

Plastic Boxes BAH what's the use
(cuz if I wanted, I could assign static IP's and gateways, and prolly break some rule somewhere somehow, nevermind)
IF my phone had a whatchacall "static" IP and I told everyone else to treat it as my gateway, uhm, (o damn)

Spelling it out, if you DARE to assign static IP's you'd better know the gateway, which is NOT the above (that's for "home internet," way different beast)

This looks encouraging (mostly unreadable, but encouraging)
Big gigantic companies buy Cisco and / or adhere to their precepts,
So (ah shit, IDK)

The phone lists very few details.

And I would not want to be overly bombastic about subjects I know very little about.

But

What is an "APN" if not a type of a gateway?

If my phone answers to a higher source and That source has an IP address, I don't know what that address is, or where to look.

it's my *router* spilling the beans:

Ip Address (of the Router)

Gateway (it's either the phone or an actual gateway-address)

OK the Router's "gateway"-ip address is replying 2ms delay, too close to be a remote biggie (busy) gateway.

If I'm right, turning off the phone's internet should still get a response.
If I'm wrong, every ping should be dead.
HA!! internet off, still getting a 2ms response (after a creepy delay).
But you can't see this sentence, I cut myself off. (wait)
So my router's Gateway is not some majestic Godlike machine, just the phone.
The PHONE's router and DHCP server may actually BE what they've been saying, but that would only matter if I changed the phone to a static IP, and I would never do that.
The ROUTER is fair game.
Anyway it gets lots more complicated, what with Wifi disabling the ethernet, so if even one of those was statically set, I might be able to run wifi And ethernet, but I'm getting into stratospheric stuff.

The next link could fill a small pamphlet, apologies, but it is the googled address for the user manual for the modem I want, "Coda56."

Now you may wonder what the difference is between it and my old modem, per their manual, but the manual might be dated and wrong (I hope)

Pinche hijola ch....anyway it COULD be wrong

https://approvedmodems.org/hitron-modem-lights/ (ooo, lights (Bah)

%$#@, Peor

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SC-QAM is, "SC"="single channel." QAM I think has a long unpronounceable definition that doesn't mean very much (Quadrature Amplitude Modulation or some crap, they all get that)

OFDM is, they can really squish separate channels together (calling them "subchannels") and, uhm, exploit the poor Single channels to the max.
But I'm still stuck on WHY they put 3.0 together with 3.1, a marketing thing or what?
See cuz they can take 32 channels (in theory) and really pack them away, no room to breathe, into a couple OFDM channels, and is that what they do?
I have no clue.
Seriously.
Will I ever find out?
Prolly not.

(link)

WHY stick 3.0 and 3.1 in the same box?
To be cheap, supply chains /war /embargos?

I'm beginning to think that 3.0 and 3.1 live together in a box called "3.1", so that the company can provide a given speed at whatever technology it currently has.

I don't see the benefits yet except for the cable company.

(In some idyllic future, maximum OFDM channels could possibly be increased from present-day "2" to 4 or 8, doubling etc speed, but I'm only guessing)

My unsatisfied explanation will have to do, because I can't find any readable docs saying why they mixed versions.
I have not read the pretty picture above from reddit yet.
(A snarky, an unreadable, a long bombastic story, and a rant or two?)