I'm intrigued - I've been trying to sell my AP960cs but if I get time tomorrow I'll take one out of the box and fire it up to see what speeds I get on 2.4 Ghz. I'll report here.

OK well I've just activated one of my AP960cs on 2.4GHz and 20/40 auto bandwidth. Connecting an iPhone 13 mini with WPA2 personal security gives me a link speed of 229 Mbps with the phone next to the AP, and 154-172 Mbps when it's in an adjoining room. Firmware version is 1.4.6

How is the AP connected to the LAN itself ? If it's wired then I haven't got an answer for you, but if it's connected wirelessly back to the router then I think you'll need to activate 5GHz to get anything better than 54mbps.

Good point - I should have made it clear that my results above are with a wired connection to the AP.

Sorry for delayed response. The AP is wired through a gigabit switch back to the 2866ax router. I'm using the latest (1.4.7) firmware.

I have just done a factory reset of the AP960c and then re-applied the previous settings and now I am getting WiFi speeds greater than 54mbps, with exactly the same settings as previously, which is very strange. Not sure why Draytek support didn't suggest that as a potential fix, but it's worked in this instance. I was about to return it, so I thought it was worth a try.