Hi

I have a MacBook Pro mid 2015. I swapped it’s original 1TB for a 2TB. Two models I tried works:

The Hat SSD I got for around $ 350 on Ebay

The Samsung 960 Pro M2, with a Synthech adapter. It’s about three times the price of the Hat SSD… But the Samsung is also close to twice as fast as the original Apple SSD on my Black Magic Disk Speed test.

Be aware that the OWC external boxes DO NOT WORK for SSDs other than OWC and Apple. You have to plug the SSD to the mother board to test them (Samsung + Synthech adapter work)

You also have to run either Mojave or High Sierra.

This walk through is almost useless: it makes something long and complicated out of something simple and easy. The only thing you have to take out is the logic board in order to access the back of the display attachments. The heat exchanger may stay in too. Just be careful with the screen wires.