I have all my networking stuff visible while playing, I never see anything fluctuate or get any sort of warning icon. So what else would I be testing exactly? You and I can speculate, but only a professional would be able to clue us in with what's actually happening. Plus, systems vary from game to game, they all handle things a bit differently, or have different things they focus on. As a player though, even though I can't pinpoint the issue, I can absolutely tell something feels way off.
There's tons of threads on this issue in here, Reddit, and Steam, so I'm definitely not alone nor an outlier with my experience. Some people probably don't have any issues at all, while some probably couldn't tell one way or another. I primarily play shooters, and I have several thousands of hours in 2042 alone, so I'm probably a bit more dialed in than most. I know the maps well enough to understand what angles are very hard to fight against, and what's possible in the game.
When my first few bullets are not registering, I'm getting hit markers, so what I'm seeing in game has to be somewhat accurate. The server is ignoring it, because having lower ping most times, it's putting me behind others on the server. That's what it feels like at least.