Won't boot up and has strange charger readings

I recently got given an iPad 6th Gen, the old owner said that it gradually became more temperamental then stopped working altogether.

Plugging it into the charger (5V constantly) it starts by drawing nearly 2A which is what I'd expect but then gradually drops all the way down to nearly zero. If I try and power it on whilst on charge, it also drops to around 0.01A but this may be normal?

I need to replace the digitiser as I've noticed a tiny crack in the corner but I'm wondering whether the battery could be the cause of some problems too looking at the above readings?

Should also add that the LDI hasn't been tripped.