iPhone 7 only works with cracked screen

Hi

i bought an iPhone 7 black 128GB off a friend of my dads about a month ago. I knew it had a couple faults:

1. The screen wasn’t cracked but wasn’t responsive in some areas.
2. the rear camera lens was cracked.
3. The rear housing was covered in scratches.

So I decided to do a full housing swap and replace the screen

the housing swap went well and I binned the old lcd and put on an aftermarket one.

It showed no signs of life

It would boot up with an old cracked (but working) white LCD off my sisters phone that I had recently fixed.

So I assumed that it was a faulty LCD I bought, so I got another one off another supplier.

It still didn’t boot.

My question is, why would the phone only work with this cracked original apple display and not with ANY aftermarket ones. Should I purchase a refurbished LCD to see if that works?

i have heard about apple blocking phones that have had screen replacements so maybe that’s what it is?

Thanks in advance for any help