PlayerAdded and PlayerRemoving connections without suspecting memory leaks.

Server.lua

local Players = game:GetService("Players")

local characterAddedConnections: { [Player]: RBXScriptConnection } = {}


local function onPlayerAdded(player: Player)
    characterAddedConnections[player] = player.CharacterAdded:Connect(function(playerChar)
        local Humanoid = playerChar:WaitForChild("Humanoid")
        print(playerChar.Parent, Humanoid.Parent.Parent)
        Humanoid.WalkSpeed = 0
        Humanoid.JumpPower = 0
    end)
end


local function onPlayerRemoving(player: Player)
    local connection = characterAddedConnections[player]

    connection:Disconnect()
end


local function onClose()
    for _, player in Players:GetPlayers() do
        onPlayerRemoving(player)
    end
end


Players.PlayerAdded:Connect(onPlayerAdded)
Players.PlayerRemoving:Connect(onPlayerRemoving)
game:BindToClose(onClose)