Won't boot OS, recovery partition missing, internet recovery get stuck
I received this macbook with a broken display. I wanted to check if the board was working, so I physically disconnected the display and connected it to an external monitor. Boot got stuck at about 40%, so I tried a shortcut to enter recovery - but this mode won't open. So I tried internet recovery - a wifi selection screen appears, then it connects and downloads for about 5 minutes, after this time it restarted and got stuck at about 5% loading. So I tried recovery through the apple configurator. I connected the macbook in the dfu and start a restore, it went through - unfortunately I couldn't see what was happening on the screen after the restore was completed, because of that I waited about 10 minutes and then power it off. Then I disconnected the internal display, connected the external monitor and power it on - after starting it shows the questionmark folder. So I tried to install macOS - after trying to start the internal recovery, internet recovery started loading, I selected wifi, something downloaded, but the next loading got stuck at 45% again (like before when loading to macOS). Diagnostics startup shortcut shows ONLY a problem with the display.
I bought a Macbook from a person who had a certificate from an authorized service center with a repair price - I have an invoice and it shows that macbook needs replacement of the display, display angle sensor and the palmrest with the battery, from which I concluded before the purchase that they found that the motherboard was fine during their diagnostics.
What else can I try and what could this behavior mean? Dead SSD?
If so, can I somehow boot macOS from an external ssd ( I am unable to get to recovery mode as I mentioned above) ?
Thanks for every answer