New battery shuts down at 1-2% then white screen loop till it flickers

Fitted a new battery, the home button cable came away from the top half (screen) section when prizing it up.. it’s still all in one piece and looked like the glue had just come away (was a small rectangular piece with tiny connecters in the middle)

So now home button doesn’t work which may also be giving me this problem (as well as not being able to hold power and home button to reset / calibrate battery (from what i’ve read although other say the new battery doesn’t need calibrating..)

The phone gets to 1-2% then shuts down as normal showing the spinning grey wheel on blaxk background then blabk screen. Then when i try tk switch it back on using the power button, it will give me a white screen and grey apple logo, like it has enough power to boot.. instead of the ‘plug in to charger’ screen like i had previous to replacing the battery..

Then it will die again and give me a black screen.. then white screen again and will loop until i just get a millisecond white flicker at the bottom.. which feels like it’s going to ruin my screen.. so i plug my phone in to the wall socket and it boots fine with 2% again and charges to 100% (or sometimes i’ve noticed it sticks on 97% for hours..)

Any help would be much appreciated