Bluetooth malfunction (?) on an Apple-ID-lost iPhone X

Hello all. I’ve been having troubles connecting my iPhone X (iOS 15; Apple ID lost) to my AW6 (Watch OS 7.5) ever since I manually turned BT off after the very first connection. Apart from that very first time, no matter what I’ve tried (restarting both phone & AW), I just cannot get my AW to detect my phone nearby, despite my X showing that it’s already connected to the AW every time I turn on BT on both devices. At first, I thought it was a firmware issue on either device and simply upgrading the OS would solve the problem, but no: the jump from iOS 14 to 15 didn't do it and somehow my AW encounters unknown issues while trying to search for the latest update. As mentioned, I cannot unpair my phone as it requires the password of my long-gone Apple ID. Is there anyway to restore AWs to their original state? I would love to know, otherwise I reckon I'd have to buy a new phone? Thanks for reading, looking forward to your responses.