What Arduino modules and what base should I choose in order to send/receive SMS?

Question

Arduino

Good day!
There is a task to make a mini computer for sending / receiving SMS. I would also like to have the ability to programmatically make calls (without voice and sound output, just for the call to go through).
The whole difficulty is that the device is sharpened for the Tele2 operator, and this operator only works in 3g and 4g networks. Because of this, the lion's share of ready-made solutions disappears and the price tag of a cellular communication module grows. In order not to be mistaken and not to miss some points, I decided to ask for advice from knowledgeable people :)
Briefly specify the requirements for the device:
1) Internet access via Ethernet
2) The ability to connect several cellular modules to one base (up to 5 for sure, preferably up to 20 -30)
3) Sending / receiving SMS in 3g network (tele2)
Optional item:
4) The ability to make / receive calls in a 3g network (tele2)
I ask for advice on what base and what modules are needed for these requirements
I would be grateful for your help

Answer 1

I would not be wiser - I would take an openwrt router and plug a usb hub and compatible modems into it.
You can also split the board for a dozen SIM cards and switch them in turn with a single usb modem.

Answer 2

3) Send / receive SMS in 3g network

+ $30-$50 to the nameplate right away, which is already comparable to a whistle and what for that arduino

Answer 3

Perhaps solutions from the Orange Pi IOT line can be considered.
But they do not fully meet the requirements you specified.
Orange Pi 3G-IOT-A
Orange Pi 3G-IOT-B
Orange Pi 4G-IOT

Answer 4

mega2560 + w5500 + sim800 (in 3g I really don’t know if it will work or not)