Galaxy S5 Screen Artifacts, Overheating & Wake-Up Issues: Possible Motherboard Failure?

Hello.

I have had the Galaxy S5 for several months - everything was flashing until the last week.
First, sometimes so-called artifacts appeared in the upper part of the screen - I thought the application was falling apart - I was leaving the application and the problem disappeared for some time.
Later, I noticed that the phone was getting quite hot in one place:



Every day this problem is felt more and more.
Recently, the phone after switching off does not want to wake up - the phone after restarting the screen restarts.
Interestingly, sometimes this problem appears after 2-3 minutes from turning on and sometimes for 2 hours nothing happens.

I cleaned the phone to zero (factory settings), no changes, uploaded a new soft (odinem) - no changes. I replaced the battery (from another S5) - also unchanged.

Did the motherboard fall? Don't you know if it can be more diagnosed without returning the phone to the service? Will it be the fault of the screen or the motherboard itself?

Below are videos showing the problem





Have any ideas ?

It doesn't look like a broken display, so the most expensive parts of this phone are rather ok.
I would not take the plate for S5 myself, without experience, because the display costs almost as much as the phone, and it is very easy to damage it.
How do you press at the top around the speaker something is changing or the picture is unchanged?