I'm out of ideas to fix multiplayer lag

Things I have tried:

• setting frame cap from 120 to 150 in the registry

• setting launch options to -dxlevel81

• setting launch options to -dxlevel80

• disabling steam overlay

• disabling steam cloud synchronization

• disabling display scaling on high DPI settings

• having all computers with a wired connection to the router

• disabling the in-game score

This is really frustrating. The game will still lock up with online multiplayer. Is there a mod or third-party patch that my friends and I can use?

Was there a recent update to the game that is causing this? We weren't having any issues a week ago.

I dunno, man.

I need an adult.