Ever since covid started.

I use to have a very low internet speed and old equipment but low lag issues at all. Ever since March of last year when covid started I’ve been having so much lag I can’t even play my games. Xfinity has came out and said that covid has not affected their speed but I think they are lying. I’ve upgraded all my coaxial cables,
Ethernet cables, and even my modem/router and I still get a ton on packet loss. I’ve even switch to their best router for a few months and that did not help. I’m going crazy that I can’t figure it out and calling their customer service makes me want to pull my hair out. Any suggestions?