The choice of wi-fi distribution equipment from 3g + video surveillance?

Question

CCTV

Good day to all
The task was to get and distribute the Internet in the country - there is 3g coverage, but outside the building
An antenna was found with a cable and a pigtail adapter from n-type to ... I don’t remember what it is - still from Yota times with samsung u-200
There is also a nettop on the atom
Questions:
Will this antenna work with 3g modems?
Which modem has antenna outputs?
It is also supposed to load the hardware with video distillation from wi-fi cameras and / or access to these cameras - is it possible to hang it on some router with *wrt or take your own nettop and load it?
If not a nettop, then which router should I take for these tasks?
I apologize in advance for the confusion and thank you for your replies.