Chosen Solution
I replaces the volume and power flex cables but the phone wont turn on. During the process of the replacement i removed the battery which i was kinda harsh on. Would this be a new battery problem or logic board problem?
Being “harsh” on a battery removal could have caused some pry damage; tiny surface mount components that are ripped off the logic board. Some of them are so tiny (see image below, look at the smallest component for scale) you’d be hard-pressed to see them unless you were specifically looking for them. They are, at times, indistinguishable from dust. If you have a good magnifying glass or jewelers loupe, look along the edge of the logic board to see if anything is amiss. This kind of damage can certainly cause an iPhone to “die”. This is repairable by a qualified micro-soldering repair shop.
