Hi @jensendash,
Did you mean that you need to backup the device before doing a hard reset?
If so have you thought about backing up your data to a PC via a USB cable?
@jensendash
The computer idea was only for data backup, not for resolving the WiFi/BT issue. Manufacturers assume that users regularly backup or sync their data to the cloud via the mobile phone network data connection that's why they provide free cloud storage, so generally needing a computer for backup before doing repairs wouldn't be necessary.
If the WiFi and BT both turn on but cannot detect or connect to networks or BT devices try using the phone's WiFi as close as possible to the home network router i.e. <10cm and check if it now detects the network and maintains a stable connection.
If it does then there may be an antenna problem with the phone.
Whilst replacing the screen the WiFi antenna cable may have accidentally come loose from the coax connector (either end)
Unfortunately if this is the case, you will have to disassemble the phone to check.
Here's the ifixit Google Pixel 8 Pro Logic Board Replacement guide that may help. See Step.43 and Step.44 for the antenna cable connections
Did you get an OEM replacement screen? I thought that the fingerprint scanner was a part of the display assembly.