Setting up Zyxel Keenetic routing to access networks via the PPtP protocol. How to do?

Question

VPN

Good afternoon, comrades.
I have a network organized on Zyxel Keenetic according to the instructions https://zyxel.ru/kb/4246
Everything works fine except for one moment. I would like to connect to the network from a phone or another computer and get access not only to the local network behind the router running the VPN server, but also to other clients.
I tried to manually register routes on the Windows client, similar to what is written on the router according to the instructions, but this did not lead to anything. :(
And there is also a problem with creating routes on an Android phone. Therefore, I would like to have a transparent solution that does not require routing on the client, but to receive it from the server. That is, in this case, from a router with a VPN server.
If anyone has ideas, you can use the original data from the Zyxel instructions https://zyxel.ru/kb/4246
Thank you.