We have recently upgraded to fibre optic connection and I’m getting 150mbps download speeds (only 8.4mbps upload speeds) and ever since I’ve found any online multiplayer games for the PS5 to be almost unplayable. I have port forwarded, set up DNS servers and have the console wired into a BT WiFi Disc (unable to plug directly into the router because of layout of the house) does anyone know how to rectify this? Got FTTC in hopes in would provide faster speeds and reliability yet I’m completely unable to use my console for multiplayer games now, any help would be good thanks.
You really need to wire up directly to router for best performance.
What other activity is on your network when you have issues?
As @Stu_H has said, a direct wired connection to the BT Home Hub is the only answer. Any form of wireless connection will introduce latency, as wireless channels are shared amongst other nearby wireless routers and devices. Signal level is misleading, as it cannot tell you the actual wireless channel availability, only its strength.
Have you used PingPlotter just to see if that helps to point to an issue?