How do i fix this moveto problem, it s very annoying ?

Problem:

The reason it is taking longer than 3 seconds to spawn another enemy is because of this line:

clonedEnemy.Humanoid.MoveToFinished:Wait(1)

Explanation:

It is waiting for the spawned enemy to move to the target positions in the path, preventing the script from moving forward.

To fix this, there are two solutions that I use. This solution will solve your issue, although you may notice a slight delay in your enemy moving as spawn() has a builtin wait() into it before the code within it executes:

spawn(function()
    clonedEnemy.Humanoid.MoveToFinished:Wait(1)
end)

The above code is about equal to this:

coroutine.resume(coroutine.create(function()
    wait() -- this doesn't need to be here, it is showing how spawn() works
    clonedEnemy.Humanoid.MoveToFinished:Wait(1)
end))

Solution:

To solve your issue, I recommend using coroutine. This will allow your while loop to continue moving through the code at the same time your enemy is moving, without a mandatory delay.

Modified Code:

-- Services --
local ServerStorage = game:GetService("ServerStorage")
local PathfindingService = game:GetService('PathfindingService')
local replicatedStorage = game:GetService('ReplicatedStorage')

-- Variables --
local IntValuesFolder = replicatedStorage:WaitForChild('IntValues')
local EnemiesFolder = ServerStorage:WaitForChild('Enemies')
local WaveNumber = IntValuesFolder:WaitForChild('Wave')

-- Actual Coding --

while true do
    wait(3)
    local clonedEnemy = EnemiesFolder.Attacker:Clone()
    clonedEnemy.Parent = game.Workspace
    clonedEnemy.HumanoidRootPart.CFrame = game.Workspace.EnemySpawn.CFrame + Vector3.new(0,2,0)
    clonedEnemy.Humanoid.WalkSpeed = 5
    local path = PathfindingService:CreatePath()
    path:ComputeAsync(clonedEnemy.HumanoidRootPart.Position,                        game.Workspace.EndLocation.Position)
    local wps = path:GetWaypoints()
    coroutine.resume(coroutine.create(function() -- added
        for i, wp in pairs(wps) do
            clonedEnemy.Humanoid:MoveTo(wp.Position)
            clonedEnemy.Humanoid.MoveToFinished:Wait(1)
        end
    end)) -- added
end

Conclusion:

Any more questions you may have can be directed to me via Discord (phxntxsmic#2021).