Chosen Solution

its just a small question and repaired phones before but not with swollen battery’s. What is a safe way to remove this battery or can i just heat up the back and remove the glass or is this dangerous with the battery.

How can i safely remove the battery?

If you use a little 99% ISO rubbing alcohol you can use something like an eye dropper or pipette to disperse it under the battery just don’t use too much as there is a whole under the battery that goes right to the display. Alternatively you could use some heat and gentle prying with a plastic pry tool.