Apple watch series 2 pairing/update issue.

Ive purchased a series 2 watch back in 2016 when it released and used it with my iphone 6s. It worked just fine out of the box but i havent used it since 2018 when i upgraded to an iphone xs. Yesterday i came across it and after letting it charge for a few hours i had a look at it and it was working just as good as before. However when i reset the watch to factory settings and tried to connect it to my phone it was not pairing. Tired to use the camera for pairing with no luck as it just made the whole app kinda freeze as in the cancel option disappeared from the top right corner and manual pairing became unavailable. After about a minute or so it threw me back to the start pairing screen. Ive tried manual pairing as well but the 6 digit code does not appear on the watch. I kept trying for hours but nothing seems to work except doing a hard reset on the phone and then i am able to scan the screen and im given the option to update the watch so it can finish pairing. Upon selecting update now nothing happens but the button turns grey and after about a minute it just takes me back to the start pairing screen (6 digit code also appears but doesnt connect to the phone at all just stuck at at loading screen). After each failed attempt a hard reset is required otherwise i wont even get this far. Im running the latest ios on my phone and ive tried everything that ive seen online but nothing seems to work. If anyone could help me that would be much appreciated!