How to make NPCS not cause lag but also decent movement using pathfinding?

I am currently working on a round based game that requires about 36 NPCS that randomly chooses from about 45000 different part to walk to with pathfinding, but their script causes lag, waits a little bit after walking to each waypoint, and also cause wait() to wait a lot more longer than it should. I've tried making one script that controls the NPCS globally and also cloning 2 scripts into each NPC(one for the movement and the other for restarting the movement script if the NPC have been stuck for more than 2 seconds) but it causes even more lag. I've also tried adding a script to the client that hides all NPCS far away from their character and show the ones that are close

This is the movement script

local PathFindingService = game:GetService("PathfindingService")

local npc = script.Parent
local Humanoid = npc:WaitForChild("Humanoid")
local Torso = npc:WaitForChild("HumanoidRootPart")
local Left = npc:WaitForChild("Left Leg")
local Right = npc:WaitForChild("Right Leg")

local height = npc.Head.size.Y + npc.Torso.size.Y + npc["Left Leg"].size.Y
local diameter = npc["Left Arm"].size.X + npc.Torso.size.X + npc["Right Arm"].size.X

local pathParams = {
    ["AgentHeight"] = math.ceil(height) , 
    ["AgentRadius"] = math.ceil(diameter/2), 
    ["AgentCanJump"] = true 
}





while true do

    local path =  PathFindingService:CreatePath(pathParams)



    path:ComputeAsync(npc.Torso.Position, game.ReplicatedStorage.paths_folder.paths:GetChildren()[math.random(1, #game.ReplicatedStorage.paths_folder.paths:GetChildren())].Position)



    local waypoints = path:GetWaypoints()



    if path.Status == Enum.PathStatus.Success then



    for i = 1, #waypoints do


            cur_path = i
            if waypoints[i].Action == Enum.PathWaypointAction.Jump then

                Humanoid:ChangeState(Enum.HumanoidStateType.Jumping)

            end

            Humanoid:MoveTo(waypoints[i].Position)

            Humanoid.MoveToFinished:Wait()

    end 
    end 

end

This is the script that detects when the NPC has stopped moving for more than 2 second

local npc = script.Parent
local root = npc.HumanoidRootPart

local max_stop_time = 2

local function check(pos)
    local amount = max_stop_time / 0.1
    while true do
        amount -= 1
        wait(0.1)
        if root.Position ~= pos then
            break

        elseif amount <= 0 and root.Position == pos then

            if npc:FindFirstChild("npc_ai") then
                npc.npc_ai.Disabled = true
                wait(0.1)
                npc.npc_ai.Disabled = false
            end

        end
    end
end



while wait(2) do
    spawn(function()
        check(root.Position)
    end)
end

Client code that makes all NPCS far away invisible

local npcs = workspace:WaitForChild("npcs",5)

local camera = workspace.CurrentCamera

local maxdistance = 120






camera:GetPropertyChangedSignal("CFrame"):Connect(function()

    if #workspace.npcs:GetChildren() > 0 and camera.CameraSubject and game.Players:GetPlayerFromCharacter(camera.CameraSubject.Parent) and camera.CameraSubject.Parent:FindFirstChild("Head") then

        for _,a in pairs(workspace.npcs:GetChildren()) do
            local child = a

            if child:IsA("Model") then

                local humanoid =    child:FindFirstChild("Humanoid")
                local rootP = child:FindFirstChild("HumanoidRootPart")
                local animate = child:FindFirstChild("Animate")

                if humanoid and rootP and animate then


                        if (rootP.Position - camera.CameraSubject.Parent.Head.Position).Magnitude > maxdistance then


                            for _,v in pairs(child:GetDescendants()) do
                                if v:IsA("BasePart") or v:IsA("Decal") then

                                    v.Transparency = 1
                                end
                            end

                        else

                            for _,v in pairs(child:GetDescendants()) do
                                if (v:IsA("BasePart") and v.Name ~= "HumanoidRootPart") or (v:IsA("Decal")) then
                                    v.Transparency = 0
                                end
                            end

                        end 






                end


            end
        end
    end
end)

All I want is for the NPCS to move to random parts from a folder with pathfinding and not cause that much of a lag on the server

If I didn't make any sense please tell me, its my first post.