I've changed my battery after this question: Does battery condition have anything to do with macbook pro performance?
The performance has significantly increased, however I have a new problem.
My Macbook's Keyboard and Trackpad are not working.
At all. Only the power button works. I've connected an external mouse and Apple keyboard via USB slots. They work just fine, the problem is it's not a laptop anymore.
This happened after I changed the battery and replaced it with an iFixIt battery while going over their tutorial. I did use Listerine instead of adhesive removal, because apparently shipping them is illegal in my country.. Some comments said that's a good alternative, I'm not sure if this caused the issue or not.
After the keyboard and trackpad became unresponsive, I've read that the Touchpad Trackpad Ribbon Flex Cable is very sensitive and it easily gets damaged. I've ordered a new one and installed it, didn't help.
Right now I'm looking for more solutions on how to fix my device.
Mid 2015 MBP Retina