Vpn routing without gateway in subnet?

Question

VPN

Hello everyone,
I'm building a vpn network, and I just can't find a solution.
Given one server and 2 types of clients.
Type one (Linux): the client is connected to the network to be reached (client_1). There can be a lot of such clients, the networks to which it is connected can be different (192.168.1.0; 172.22.1.0...etc).
Second type (Windows): (client_S1) the client connects to the vpn network, after connecting it should be possible to get to the subnet of the first type (client_1).
If client_1 is configured as a gateway on the subnet, then everything works fine, that is, client_S1 can reach the subnet.
Now actually the question itself , how can you reach the subnet if client_1 does not play the role of a subnet gateway?
Another problem is that there can be many such connections, that is, there can be 5000 clients of the first type on the server at the same time, there can be 100 clients of the 2nd type, and the routes are actually different for everyone.
Below is a schematic diagram.

Answer 1

how it is possible to get through to a subnet if client_1 does not play a role of the gateway of a subnet?

It seems to me that none.
What will be the gateway for machines on subnet 192.168.1.0 if not 192.168.1.250? How will the machines go to the Internet, if not through the gateway, which is 192.168.1.250?
What do you mean by the phrase "does not play the role of a subnet gateway"?