Websites load slow or not at all despite fast internet connection

I find that my desktop browser firefox is very slow or doesn't work at all on a lot of websites like amazon or fortnine. My internet connection and computer are not the issue: 270Mbps (wired connection) Processor AMD Ryzen 7 9800X3D 8-Core Processor (4.70 GHz) Installed RAM 32.0 GB (31.1 GB usable) Graphics card NVIDIA GeForce RTX 4070 Ti SUPER (16 GB) Storage 3.58 TB of 10.92 TB used System type 64-bit operating system, x64-based processor (Windows 11) My old PC and my mobile phone runs these website fine. Sometimes the website will work for a moment, but stop and just load for ever after I open a new tab or clink a link. My task manager doesn't show any ethernet usage despite the tabs indicating they are trying to load. Refreshing the tabs does nothing and no matter how long I leave them they don't load. All my drivers, OS and programs are up to date. I have disabled my enhanced tracking protection and I don't have any adblockers. I have tried using the CMD "ipconfig -renew" and using ccleaner to clear out my cookies and cache but, nothing seems to have any lasting effect. I am losing my mind trying to fix this. Why can I not browse the internet on my PC? Any help on this would be amazing and much appreciated. Sincerely, Calvin