TP-Link Wireless Speed Issues With MR80X Router Despite 500 Mbps Connection

I own a TP-Link Mercusys MR80X router and have a 500 Mbps internet service. However, the router does not provide more than 310 Mbps on wireless connections under any circumstances. When I contacted customer support, they were not solution-oriented and only blamed me, insisting the problem was on my end without offering any constructive solutions. Note: When I contacted customer support, they claimed the issue was related to the cable. To verify this, I used the same cable to connect my computer directly, and I received speeds exceeding 500 Mbps. I also conducted a speed test while being 10 cm away from the router, and I am attaching the result as a photo. Device details: Firmware Version: 1.1.3 Build 20240718 rel. 58004(4555) Hardware Version: MR80X v2.0