Macbook Pro not working unless screen is tilted 20 degrees

Hello Apple Support

A couple of days ago, my Macbook Pro 2018 started acting very strange. After several days of mostly black screen, I managed now and again to have few steady moments. Within these moments I managed to reset NVRAM, SMC, disable dark mode + true tone and automatic graphic switching. I also drained the battery completely and ran diagnostics, that didn’t show anything unusual. 

Lately the Macbook’s been malfunctioning in the same manor: If the screen is tilted up in a 90 degree angle, it won’t work - if it isn’t black, it’s a screen freeze (I can’t move the cursor nor use the keyboard). However, if the screen is at a 20 degree angle (right before standby-mode), I can most of times manage to login.

Therefore I can only operate my Macbook with an external monitor. Once I’m logged in, this works flawlessly. But it’s a pain in the ***.

Any suggestions to how I fix this problem?

Sincerely

Sam