There have been ways to lag the client as long as you’re viewing the chat. It has come in many forms. It could be as simple as 1 sentence with special characters. As long as you see the chat it will lag you.
So yes, the dot COULD be this exploit.
Turn off chat completely and spend some time on the server. If you don’t experience the same lag as consistently, this could be an indicator. But it’s really hard to say.
Lag can be induced by simply raiding a base regardless if it is resource intensive. I could usually tell if someone was being raided on an active server simply by the lag.
It would be extremely hard to prove esp and is probably the most common cheat available. Why is it hard? Because there are usually dedicated scouts in serious pvp clans. Being one, I would have found you.
Never, ever, take your advice from Youtube videos for “hidden” spots, they’re no longer hidden.