I know this. I've been playing CoD with my R1 for 4 years now. There is no 'sweet spot' for me. Doesn't matter where I put my sliders, what ports I prioritise, what ports I forward. Nothing makes any difference. Everything was working fine, as I've said many times until they updated the game. Ever since that update, nothing makes any difference.
Again, as I've said many times now, I've been speaking to many many YT'bers and Twitch folk who are having the same problem and only since that update. Hence... its the game and nothing I do will change that.
I had my 'sweet spot' before that bloody update. Was working for months. Now nothing works. Frankly the game plays better on ISP wifi for some reason.