@Jenuma, setting up port forwarding at the router level wouldn't be a solution to your problem in any case; it's needed only when you are offering services (like a web, cloud, or VPN server) from within your NATed internal network that should be reachable from the outside at your public IP address. Setting up a port forward means nothing else than deliberately punching a hole in your firewall to allow incoming connection requests to pass through and be routed to a corresponding host/service within your network. A port forward does not influence already established TCP/IP connections, regardless whether the initiation request came from within (like from your ESO client) or without (the default firewall behaviour is to drop/block them) your network.

Could you please post the stats of your MB, including macOS version, and excluding S/N? You'll find them under Apple Menu > About this Mac.

You might also want to refer to my Mac 64-bit client FAQ (link in my sig below) to see whether your Mac has any bottlenecks regarding RAM or GC.

@Jenuma, if you are on WiFi, try connecting your MBP directly to the router via network cable. This will rule out any wireless data rate/transmission problems that might occur in your home. Your internet connection doesn't run over a cellular network like LTE, does it?

You could also try to rename, move, or even delete the folder

Documents/Elder Scrolls Online

within your profile/home directory. This will reset any setting, disable any addon, and will give the game a fresh start, as this folder gets rebuild from scratch at the game's next launch.

You can also try to invoke the repair function in the Game Option menu of the Launcher. This will verify the local game field and repair them if necessary.

Last question, does your MBP run on a HDD or SSD?

Having the exact same issue. Just started happening today. I got rid of addons and still can't load a character. I have a great internet connection and have never had this issue until today.