Hi...That's really good information. Very similar to my circumstances and definitely worse the past week, however the issue has been there for a while. @Ripshod above has tried their best to help on another forum and the "Gateway" issue referred to is absolutely the source issue - I am just hoping I can optimize my router better to possibly reduce and stabilise the latency a little better. I've done a reset so we'll see how that goes over the next few sessions.All these are good troubleshooting techniques and hopefully something fixes it for you. I do have a question for you though.
Did your issue just start recently? I'm a fellow Warzone player. I typically have 20-30ms ping during games. Occasionally it'll be in the 40s. All this week my ping has been higher than usual and it's been occasionally spiking. The game has been stuttering too. Everything else in my house has been running fine and both my sons game and haven't complained about any lag on their games (and trust me, I hear about it immediately when it does lag, whether I'm sleep, in the bathroom, at work, or whatever lol).
The new update has caused a lot of issues and the servers have been worse too. The COD Warzone reddit is full of people complaining and less people have been playing which does lead to it to taking longer for lobbies to fill. It could just be the game since everything else seems to be working well for you. Hopefully they get the game and servers fixed soon.