often see C taking headshots at PL who are invisible due to plants.

We still see a lot of players sniping at other players who are clearly obscured by plants and trees. Naturally, they take damage, and even though they stay in the same place for long periods of time hiding behind obstacles, they can still see other players and calmly land headshots.
The time for defending cheaters is over.
Ban them.
Skill matching is also completely broken, and the unfairness and lack of gameplay still result in people dropping out or freezing up about one in two matches.

For now, please just try to make the game work.