It sounds like your LED inverter or loose connection ( it has one just integrated into the screen unlike the older LCD backlit models)......... when it goes blank, which i assume means black can you see any text on the screen using a flashlight?
If so sounds like a backlight issue and the screen would need to be replaced........ usually based on my somewhat limited experience with this model these LED backlights just fail completely however like the older ones intermittent issues can happen.
Based on the question i imagine it works fine with an external monitor?
Checking for a loose or bad connection problem via the cables....... would be something i would check first esp since you mentioned keeping pressure on part of the frame to keep your screen on............
ribbon cable if you can't see anything at all on the screen......
...... can be a tricky diagnosis having the computer half apart testing and looking for the result.
They are some other similar questions here on ifixit that have been asked about this issue which should help having a significant amount of information.
I would provide more information, however i usually work on the older models, and PC's etc..........so been awhile, over a year maybe since i had to work on one of these models.
Hope this info helps, it's been couple of days since you asked your question and hopefully this info will point you in the right direction.