stuttering motion 2d objects

hi, guys.I know anny question has already been here, but has not been able to solve this problem.

I am try: -fixedDeltaTime -smoothDeltaTime -deltaTime

use AddForce,Velocity,just tried to move the coordinates, and still I see stuttering when driving. interpolation included. FixedUpdate and Update - and still I see stuttering when driving. interpolation included.

I had already lost two days to find a solution, I was tired and did not know what to do

         if(Rock1.transform.position.y > 28f)
             Rock1.transform.position = new Vector2(Rock1.transform.position.x, Rock1.transform.position.y);
         else if(Rock1.transform.position.x > 1f) {
             Rock1.velocity = new Vector2(Rock1.velocity.x, speedUp * Time.fixedDeltaTime);
             //Rock1.AddForce(Vector2.up * 220 * Time.fixedDeltaTime * 100);
             //ban1 = false;
         }
         if(Rock4_1.transform.position.y > 43f && Rock4_2.transform.position.y > 43f) {
             Rock4_1.transform.position = new Vector2(Rock4_1.transform.position.x, Rock4_1.transform.position.y);
             Rock4_2.transform.position = new Vector2(Rock4_2.transform.position.x, Rock4_2.transform.position.y);
         }
         else if(Rock4_1.transform.position.x > -1f) {
             Rock4_1.velocity = new Vector2(Rock4_1.velocity.x, speedUp * Time.fixedDeltaTime);
             Rock4_2.velocity = new Vector2(Rock4_2.velocity.x, speedUp * Time.fixedDeltaTime);
             //Rock4_1.AddForce(Vector2.up * 220 * Time.fixedDeltaTime);
             //Rock4_2.AddForce(Vector2.up * 220 * Time.fixedDeltaTime);
             //    ban2 = false;
         }
         if(Rock2.transform.position.y > 35f)
             Rock2.transform.position = new Vector2(Rock2.transform.position.x, Rock2.transform.position.y);
         else if(Rock2.transform.position.x > -1f) {
             Rock2.velocity = new Vector2(Rock2.velocity.x, speedUp * Time.fixedDeltaTime);
             //Rock2.AddForce(Vector2.up * 220 * Time.fixedDeltaTime);
             //    ban3 = false;
         }

anyone can help?