GL-MT6000.
I've been having a problem with DDNS (xxxxxxx.glddns.com) for a few days now. Previously, it worked properly for several months. I use it for a VPN server (VPN tunnel). I don't have a public IP.
Alternatively, what alternative solutions do you propose for the Wireguard server (remote access to the router and LAN and WAN networks) - AstroRelay, Zerotier, Tailscale, Firezone, etc.
To build a VPN server, the public IP is required.
If create a virtual network without public IP, you can try AstroWarp, Zerotier, and Tailscale.
It turned out that the ISP had introduced CGNAT and taken away the public IP. How can you bypass CGNAT? Will AstroWarp, Zerotier or Tailscale help solve the problem?
Rather ask your ISP for a static IP address (they may give static IPs on request or for a fee) if they are only giving you CGNAT option then you will have to choose one of the following services you mentioned. They can bypass CGNAT.
Which is safer: a dynamic IP address with Tailscale or a static IP with DDNS and a WireGuard server ?