Chosen Solution
So replacing the battery from ifixit went like this. After replacing the battery the phone was stuck in boot loop. I tried a few possible solutions but whitout any luck. Luckily i did not throw old battery away so i replace the new one with old one. Phone did turn on and it is working. I switch it again to double check if there was bad conection but same story as before so i switch it back to old battery and again it is working. What do you think went wrong ? Update (12/19/2020)
Here are pictures
You would need to rule out the battery first. But since this is an iPhone 8 it could be the battery connector on the logic board. If the old battery had a slightly bigger connector the new battery connector might not be making solid contact with the pins. Have a look under some magnification at the connector if it looks fine you will need to organise a replacement battery.
