Unity - Decreasing float var with "Time.deltaTime" never going down - unity3d

Question

I'm try to create a function to stop player control, but when I pass the duration as a parameter in the function, the variable keeps ina huge number never really decreasing.
public void StopAllPlayerControl(float duration) {
stopPlayerDuration = duration;
stopPlayerDuration -= Time.deltaTime;
//stop here what you need.
playerInput.enableMovement = false;
if (stopPlayerDuration <= 0) {
//restore here to normal state
playerInput.enableMovement = true;
}
}
And Im calling this funct in a Update method like this
StopAllPlayerControl(3);
Image here to show that stopPlayerDuration getsm huge but stays in those big numbers never really decreasing. huge number

Answer 1

I used a combination of both answers, organized my logic better and, in this case, I used a coroutine.
This function starts the coroutine and I can call it and control it with a bool
public void startStopPlayerCo(float dur) {
//function to start stop player courutine from anywhere.
StartCoroutine(StopPlayerCo(dur));
}
This is the coroutine that works well now
public IEnumerator StopPlayerCo(float dur) {
while (startCO) {
GetComponent<PlayerMove>().enabled = false;
yield return new WaitForSeconds(dur);
//reset
GetComponent<PlayerMove>().enabled = true;
startCO = false;
}
}
And I call it in Update Method like this:
startStopPlayerCo(2) //2 seconds, or any var for desired time

Answer 2

Try this:
float startTime = 0;
float duration = 0;
public void StopAllPlayerControl(float duration)
{
this.duration = duration;
if(playerInput.enableMovement)
{
startTime = Time.time;
playerInput.enableMovement = false;
}
if(Time.time - startTime >= this.duration)
{
playerInput.enableMovement = true;
}
}
Explaination
Step 1
Firstly, we need to check if movement is already enabled. If it is, we mark the point that we started the timer, and disable movement. We also store our duration in a variable, and reference it locally with the `this` keyword.
if(playerInput.enableMovement)
{
startTime = Time.time;
playerInput.enableMovement = false;
}
Step 2
If the timer exceeds the duration then movement is enabled.
if(Time.time - startTime < duration)
{
playerInput.enableMovement = true;
}
It is also good practice to enclose this method in a boolean lock to prevent it from being called again while the timer is running, unless you want such a feature to be allowed.