EDIT: I’ve successfully followed your steps up until the battery removal.
It’s held on with a little bit of adhesive but its completely wrapped in this plastic and the wires seem to be soldered on.
Looks like more time and tools are needed to replace this battery.
is the battery glued down? mine stopped working and i feel like it’s due to a failed battery. I need to replace it, but not sure how difficult it is to remove or what to replace with