Why is my iPad mini 4 rebooting after battery replacement

I just replaced my iPad mini 4 battery, booted it up and the battery showed 1% which I thought was strange so I plugged it into it’s charger, it then immediately jumped to 100% with the charging logo. After a few minutes of it charging it rebooted itself and keeps doing so plugged in or not. Upon every reboot it shows 1% battery with occasionally “0% remaining” under the current time. So I left it charging overnight for probably 12 hours. This morning I unplugged it, and it still shows 100% after using it a little bit the battery dropped pretty quickly within about 20 minutes to 84%. it still reboots every few minutes with a strange coloured dotted screen sometimes and sometimes no dots, sometimes solid colours and sometimes black. Then the screen goes black, Apple logo shows up, it runs for a few minutes and repeat.

Between the reboots for the short few minutes it’s alive, it works perfectly fine

I plugged it in to charge again into a 5V 2.4 A charger with a 3 foot cable. It slowly charged up from the 80s to the 90s. But STILL reboots every few minutes. I’ve completely formatted to factory settings and got through the setup as a new iPad, hard reset a few times but nothing works.

Would this be a faulty battery?