iPad unresponsive to iMac

Hi all,

I have a iPad Air A1474

Before I had it, the digitiser was replaced by a less than reputable source and as a result a few problems have occurred.

The problem list:

Power button won’t lock device, but it will turn off and on.

When plugged into iMac and I’m asked to allow the computer access, the pop up isn’t showing up on the iPad

I can’t delete apps by pressing the ‘x’ at the top left of the icons. When I delete from the settings menu the apps stay on the home screen.

What I’ve done so far to try to fix it:

Had digitiser replaced with a decent quality one by a trusted source.

Reset the iPad

Made sure the software is updated to iOS 12.

I’m stuck now. I don’t now where to go next with it. I know the cable from the computer is fine since I’ve backed up mine and the g/f’s iPhones with it.

any help would be much appreciated.

Thanks guys