GL-MT300N-V2 mango vpn server to conect to Qnap NAS

i would like to conect to my Qnap NAS via VPN trough the mango v2 and i do not what should i do exactly, i have isp router and the NAS is conected to it via ethernet and i conected also via ethernet the mango v2 i have port forwarding enabled on the isp router port 4443 to the mango router ip and i have vpn server enabled but i am stuck there because the clients doesnt conect.
if some one can show me please how can i do it from 0 in a guide step by step
thank you very much

Do you use openvpn or wireguard?

Can you give more details about the port forward? 4443 to, what is the port number on 1.199?

You mean the vpn does not connect or nas cannot connect?

i tried with wireguard but i am open to use whatever
the port on mango 1.199 is the same 4443

And can you post config of Wireguard? Did you change port to 4443?

Or can you just keep the Wireguard port default which is 51820, then port forward from 4443 to 51820

actually the problem is that i feel like the steps i followed are not the correct
what i want is to conect to vpn and be on the 10.6.0.x because i want a little bit of security to conect to the nas.

before i used the openvpn of the NAS and the vpn network was 10.6.0.x and i could reach the NAS on the

maybe i am mixing things and dont have a clear image of the steps or what should i do.