Trouble Pairing & No Wi-Fi, Very Poor Bluetooth Range

Got given a Apple watch series 4 with a broken screen so I purchased an iCloud locked series 4 for the donor screen.

I replaced the screen without issue but upon trying to pair the watch to my iPhone my iPhone cannot find the watch automatically.

I can manually pair the watch and enter the passcode displayed on the watch and have paired the watch to my phone successfully.

Upon testing the watch it finds no Wi-Fi networks at all so there is also an issue with Wi-Fi.

Whilst Bluetooth works it is only short range, if I move the watch more than 30 cm away from the phone it loses Bluetooth connection.

I know swapping the screen means NFC will not work which does not bother me but does Apple use NFC to find the watch during pairing?

Been looking over every connector and flex for damage but cant find any with my microscope. No clue where the Wi-Fi antenna is located.

Seeing as I have another watch I tried swapping the back glass, tapic engine and but it made no difference.

Anyone got any pointers on where I should be looking for a Wi-Fi issue?