Network Administrator

I want to set up a VPS (Gl.inet OpenWRT router gl-axt1800) and be able to connect to it when away with another Gl.inet OpenWRT router gl-mt3000 (without installing anything on my computer). However I am behind a CGNAT or double NAT and nothing can pass through the public IP. I have tried installing ZeroTier and Tailscale in both VPS and client routers, and I am able to make my routers ping at each other, but I cannot make all traffic go through VPS and have VPS IP and DNS. Please could you help me set up the VPN so I have IP from VPS?