Do you have any modem unit from your ISP?

like i said i have 2 sim cards - one with dynamic public IP (with that one I managed reach the huawei modem remotely (with the help of no-ip) but not the local network). Are you sure for 100% about...

Can you give me yet info about LAN address on the routers?

Hi, Can I connect this mini router with a cable to port on an existing router (at 50m distance)? Is this cat.5e or cat.6 cabel?

Other way is to use p2p in Dahua NVR, does not need any port forward or dyn ip service, just that NVR has access to internet. If the unit has p2p service.

In my opinion this is SOHO router and telnet service isn't needed for normal users.