How to combine local networks of WiFi points from different providers?

Question

Computer networks

Good day.
There are several offices and two Internet access points on the floor: one is wired (D-Link Router), the second is 4G (huawei from Yot's).
Problem:
There is a computer with data. It is connected to D-Link and has access to it over the local network as a network folder. From distant offices, the signal is very weak, but the routers "see" each other normally.
It is not possible to change the location of the points.
You can't turn someone off.
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Google has information on the operating modes of routers, but the examples found are considered only with dad, i.e. one internet source.
One more thing, you can’t call it a problem, rather an obstacle, this is what many Internet users are operating and usually at the same time. One source is not enough for all offices.
Therefore, there is no option to use the second point as a client of the first.
The current location solves the problem of "brakes", but introduces difficulties in working with data.
Essence:
The main goal is to combine local networks so that a computer with data and other equipment in the network of both points can be seen.
Thank you! =)

Answer 1

On each of the routers, use the same subnet, for example, 192.168.0.0/24, you can (though not necessarily) configure DHCP for non-overlapping parts of this network (for example, 192.168.0.1 is the first router, 192.168.0.2-192.168 .0.100 is the subnet for its clients, 192.168.0.101 is the second router, 192.168.0.102-192.168.0.254 is for the clients of the second router).