Streaming Constantly Buffering

This started about 4 weeks ago. I live in north Vancouver, WA. I have not changed a thing in my network and suddenly my NetFlix, Amazon Prime, Peacock and others started buffering every 10 min. It now does it every couple minutes making it impossible to stream a program. It took me 15 min to finally get into Xfinity.com. I have gone through your troubleshooting twice. You replaced my modem and no help. Your final answer is its my equipment. Exactly how do 3 TV's, 2 Laptops, 2 Iphone 16 pros and a fire tablet all go bad at the same time?