If you've been getting booted constantly while playing, apparently you may need to forward some ports that Sony doesn't list as the main ports to allow forwarding for on a PS4... besides the main ports you may already have forwarded, I was told to try forwarding ports TCP 10040 through 10060. Also forward UDP 50000-60000. I tried everything until this and no longer getting booted during gameplay. This should be made more public by ESO support really since it was the only thing that helped.