If there is peekers advantage, it favours low ping players. If im staring at a corner waiting for you to peek, you are going to roll around and see me before I see you do that on my screen because of the delay. If I did the same to you, you will probably see me at the same time I see you, since my inputs are delayed.
This game is server side, the clients decide NOTHING as to what is happening. The client has zero input, its basically just a TV screeen outputting what the server has decided.
When you make any inputs, you are asking the server to do that. The server then decides if you actually are doing that or not, and tells the client to output the results. Thats why I can fire at someone, see me shell hit them, and it do nothing because they have shot me at the same time and broken my barrel or killed my gunner or something. This is because the server has received the other players request to fire, fired the shell, its hit my tank, and the damage was calculated before the server received my (200ms delayed) request to fire.
The client is probably predicting what is happening to an extent to reduce input lag and smooth out gameplay and the connection, hence why I still see my gun fire and my shell fly towards them, but as soon as it receives the servers decision, that is what takes over. There is no having to choose between clients, because the clients have no say in what is happening.
Other games, mostly faster paced FPS games, have clients that can tell the server whats happened, because doing it all server side is too slow for the pace of the game. Thats where you’ll find things like Peekers advantage. The worst game for this Ive played was PUBG. The peekers advantage was huge, but it effected both the high and low ping party equally. So if a low ping player peeked a corner on me in that game, Id die before even seeing them. But if I peeked on THEM first, Id kill them before they even saw me. If used right it could be an advantage to the high ping player, but in that game I still found it a net disadvantage because it meant I ALWAYS had to be pushing. I couldnt sit and hold a position, or play defensively because Id lose the fights 100% of the time. I always had to be the one running around the corner first. It sucked.
The only other game Ive played with “high ping advantage” was Battlefield 4. Which “allegedly” gave an advantage to high ping players because hit registration against them apparently sucked. But having played on high ping in that game a fair bit especially as the game got older and Oceania servers became rarer, I havent felt it, because my hit reg also sucked ass. Every advantage I had over them, they also had over me in the same way, so it sucked equally for both the high and low ping player. I dont really consider that to be a net advantage for high ping personally