Phone won't start after battery and charging port replacement

I was having the usual issues with the Pixel 3XL charging port not working for some reason. After about a year of dealing with this, I broke down and bought a replacement charging port and battery for the phone. Since the charging port is deeper in the phone, I replaced that first and checked to see if it would charge. It did.

Then put pieces back in and then replaced the battery. After fully reassembling the phone, I can’t get it to charge or turn back on. I went back through and made sure every connector and screw I had touched was in place and intact. Nothing. I even put the old port in and tested it. Nothing. Plugged in the old battery instead of the new one. Nothing.

Anybody got any ideas for what may have gone wrong and what I can do to fix it?