@nazar30396 if you are sure that this is a hardware issue, you will have to replace the complete display assembly. Your display and the touchscreen are fused, Since iFixit does not yet have a guide for this, use [https://www.nadiemellamagallina.com/en/manuales/smartphones-1/samsung-4/samsung-galaxy-a12-nacho-1361/pantalla-completa-12291|this one] for now. Replacement displays are readily available at many online stores. Just make sure that you get the one for the exact version of your phone.
While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.