Not booting and possibly not charging

Hi, I have got an iPhone XR for free from a friend that doesn't work and I am trying to fix it. I do not have any tools (multimeter, voltage detecters) and I do not want to take it to a store OR replace any parts. It shows signs of life when plugged into a wall outlet but only some times with a MacBook. The screen is broken and shows lines on it (I do not want it fixed either, I just want the phone to boot, I don't need to see screen) and the lines are red and when I press volume buttons it appears for 5sec which indicates to me the battery charging screen is showing. The other times it shows what I assume is the Apple logo bootlooping which indicates to me the battery is faulty. Some of the times when I gently push on the part of the screen the battery connector is located, it will put it back to what I assume is the battery charging screen.