Question LG G3 motherboard stuck in case

[Bubble16]

The screen is broken so I bought a new screen for my G3 and I unplugged all sockets and the top of the motherboard where the soc is stuck.
I think someone applied thermal paste on the soc and it dried because of the heating problem (it's a used phone)
Is it the problem or how can I take it off?

 

[Zizo007]

This is not a cell phone forum. You will have better luck posting in XDA developers.

And the LG G3 is very old and worthless, we are in the G8 time.
Not worth the time and money.