Chosen Solution

I recently used IFixit’s guide to replace my iPhone 6s battery, and the battery life, or speed did not improve. I can barely make it through half the day on minimal use. Should I ask for a replacement? Phone is still heating up to an insane amount and I don’t know what to do.

there is always a possibility. Most often, if the device is heating up substantially, it is a short circuit, however, i will never say that that is the exact reason. in order to test the theory, you would need another battery. if a second battery is causing the exact same issue, then you can 110% chop it up to a short circuit.