PS4 Pro has a bad internet connection despite 1Gbit / s line, what could be the problem?

I have a 1Gbit / s line, with the speed test on my mobile phone I get 800Mbit / s but on the PS4 Pro it looks completely different. On the PS4 I unfortunately get max. Only 170 Mbit / s with internet failure, no idea why. : /

I've already tried everything, unfortunately the problem is still there, it's quite annoying, especially with FIFA

And how is the PS4 connected? WIRELESS INTERNET ACCESS? Maybe the distance to the router is too great.

Both with LAN and with WLAN.

The distance to the router is approx. 4-5 meters. (It's in the same room)