Whole display SOMETIMES showing horizontal lines, no phone damage

Hello guys,

My Samsung Note 9 is not damaged and display is acting very strange, there are to many black horizontal lines on my whole display and display is also dimmed down, but when I turn screen off and then after few seconds I turn it on then horizontal lines are gone. Then again when I use it for few minutes then lines are back again.

Is it a connector issue?

Do I have to replace whole display?

Can I do it on my own?

Plz help me.