I replaced my screen and now the phone seems to get stuck bootlooping?

It sounds like either your replacement screen is faulty or that something wasn't done correctly during the replacement procedure. There could be many reasons for a device to bootloop, however, since this occured upon a screen change, it's most likely hardware related. It's mostly about power when we're talking about hardware-related bootlooping, and the phone not being able to draw the correct amount of current from the battery for it to function normally.

These could be some of the causes of this issue:

• Something was incorrectly done during the repair, such as not properly connecting a cable.
• Something was damaged during the repair, such as unintentionally stabbing a component on the motherboard.
• The replacement screen is faulty.

I don't know where you bought the replacement screen from, but as long as it's not a cheap knockoff, it shouldn't be the issue on the first hand. Here's a link to a replacement screen from iFixit.

Troubleshooting

• Turn off the phone, let it charge for a bit, and then try to turn it on again.
• Open the phone up, take a close look and make sure that all the cables are properly connected and nothing looks broken.
• Try the old display again and see if that works. If it does, you might be dealing with a faulty replacement screen. If that's the case, then contact the seller you got it from and ask if you can get a refund or a new display
• Read the guide again and make sure that you've done everything correctly. Even errors that seem small could result in the repair not being successful. Also remember to read the description and other notes, as they might come in hand.

@amjtech Thank you so much for posting your answer and adding your video! I've run into the exact same issue and I would not have realized why had you not written that post.

I do have a question though: My phone is currently stuck in a boot loop and I can't figure out how to turn it off safely. Should I just let it loop until the battery dies?