Slow motion problem

I made some scripts to slow down the time whenever an object hits a collision box that activates the slow motion. The slowdown time is 1 second but the slow motion never stops. I also tried to write a new script that deactivates the slow motion when the object is hitting anything else than the slow motion collision box I made and it stops the slow motion but my objects start to move 2 times faster than normal or so. Can anyone tell me what is wrong in here because it seems like I can't figure it out. I will let the scripts below, the first is for slowing down time and the second is for making it "normal" (but not normal because it doesn't work...)

 using UnityEngine;
 
 public class TimeManager : MonoBehaviour
 {
     public float slowdownFactor = 0.2f;
     public float slowdownLength = 1f;
 
     void FixedUpdate()
     {
         Time.timeScale += (1f / slowdownLength) * Time.unscaledDeltaTime;
         Time.timeScale = Mathf.Clamp(Time.timeScale, 0f, 1f);
         if (Time.timeScale == 1.0f)
         {
             Time.fixedDeltaTime = Time.deltaTime;
         }
     }
     public void DoSlowmotion ()
     {
         Time.timeScale = slowdownFactor;
         Time.fixedDeltaTime = Time.timeScale * .02f;
     }
 }

Slow motion script above ^ and stop slow motion script below.

 using UnityEngine;
 
 public class TimeManager2 : MonoBehaviour
 {
     public void StopSlowmotion()
     {
         Time.timeScale = 1f;
         Time.fixedDeltaTime = .02f;
     }
 }