@fu5ha If my understanding of "rollback netcode" is accurate, that would describe what Valve games on Source Engine use. I think most modern FPS do this too. HL1 engine used a different method iirc.
The sub tick feature is sweet, makes me wonder if other engines do anything similar
The best solution will not be provided to you.
When I think about what i learned in my time in L4D2--both coding and esports--this phrase always comes to mind