If other devices are getting full speed then your line is working normally and it suggests the issue lies with the PS4 or PSN.
How are you testing the PS4 speeds? The Sony speed test built in to the console (and the PS3 before it) is notorious for not reflecting the true speed of your connection. Not all speed tests sites work in the PS4 browser but even the ones that do never get up to the same speeds on my PS4 that my PC can achieve, even when both are connected via Ethernet.
It should show better speeds than the built in test but as I say never the full speed of the connection.
I have always used Ethernet with my consoles so don't have experience of the PS4 WiFi. I do know that the Pro supports both WiFi bands, 2.4Ghz and 5Ghz and it is possible that it is only connecting to the hub via the slower 2.4Ghz band. There are instructions for forcing the PS4 to only use the faster 5Ghz band here: