Been playing about a week with a slightly upgraded CPU (Ryzen 1700 > 2700x)
Still see frame drops, but they don't seem to be as dramatic which makes playing through them easier. Even though all the same stuff is happening I've been feeling like the game is a lot less in the way, and when I see performance issues that it's more likely the connection or something to do with the other person.
I have to wonder how much the other person impacts you regardless of what you have going on. Like I ran into TheArmory right after the upgrade and it ran mega smooth, but that certainly isn't always the case. There are a surprising number of people running the game with low fps and you don't even need perfect 60fps to get a green score. I'm not sure what happens on my end when someone else only kind of gets 60fps then hops online and starts getting hit with net delays and high rollback counts (I wonder if the benchmark simulates rollbacks since they have performance impact).
There are a lot of stages that seem to be asking for trouble. "Special Forces Desert Command", "Kotal's Koliseum", and "Black Market Alley" probably being the worst.
I've had good spells before, but it seems more legitimately improved, and like this is the only upgrade that the issue has actually responded to. There are better gaming CPU's but it still seems like overkill to need a 2700x to play smoothly. Especially since the game used to run great and my old CPU never appeared to be breaking a sweat.
Anyway, it's more enjoyable now, and I've probably complained enough about the issue at this point.