Why do randomly I lose control of the screen?

Hello! I've experienced a similar issue like this. You might have tried a few of these things already so you don't have to follow the steps in order. Here's what I would recommend.

1.) While it may seem obvious or stupid, try cleaning the device with a damp, microfiber cloth. If you can't get ahold of one, a paper towel will do. Unplug the device, shut it down, and gently wipe. Based on your issue that likely won't solve it, but it's worth it for the following steps.

2.) If you don't have a screen protector, skip this step. However, if you do, carefully take it off. Repeat step 1 again but you likely won't need to be as particular with it.

3.) If you don't have a hard case, skip this step. Sometimes if you drop a phone in a hard case, the case will bend. This can affect the screen and cause further issues with the responsiveness of the display. Just taking off the case might do.

4.) Force Reset your device. Apple explains it fairly well here. Select whatever iOS version you're running. It can't be iOS 16.

5.) If the problem still continues, I can almost guarantee that your issue was caused by a bad repair job. If the job was rushed, improper seating of the display cable as well as a dozen other issues from faulty repair/parts can cause this. I would personally repair it myself, but if you can't in your current position, I would see if your parents can bring you back to the repair shop or another one available. While most technicians know what they're doing, it's entirely possible for a few negligent ones.