MacBook Pro strobe flicker screen and stops when I move the mouse.

Hello, I have this MacBook pro that was given to me by my brother. It had a lot books on it. But everything was fine till yesterday.

I downloaded Photoshop and my macbook froze. I did a hard shutdown. It took a while to load and started glitching alot to where I see the login screen in the backgroud of the loading screen logo and flickering.

Then I noticed it starts to do this flicker thing even more during reboot etc. Sometimes it not that noticeable but when my cursor freeze it gets worse. When I open some programs, my macbook start to lag and freeze and flickers more.

I have tried the reset NVRAM with command keys.

Looking at my Disk utility and reinstalling Macintosh HD

Still didn't work

I talk to Apple support and they said they dont see flickering on their side. Told me the things I already done.

I am hoping that I dont need to go to the apple store to get to get fix cause I might be in trouble by my mom. This is the second laptop. The first had a screen crack

Any solutions