Update**after the online and phone support. They stated it was my battery. I still don’t agree but I did pay $94 for battery replacement. That included shipping, part and labor. I was sent a replacement watch, apparently they don’t replace batteries. Now I could have used that money to upgrade but my watch has sentimental value (anniversary gift) and I have stainless steel version. Since getting the replacement I paired it with my phone, charged it but didn’t use it. Waiting for screen protectors. The replacement watch drained from 100% to 77% while sitting on my dresser while I was out for work. I was gone maybe 8 hours total. I did another chat because I didn’t understand why. I was told to unpair, shutdown, turn on and repair. I did do that. Today I left it at home again fully charged. I been gone 9 hours and battery is at 94% after returning. Regardless I still think the update did something to my watch to begin with. I went from being able to go almost 2 full days on a complete charge Pre-update to battery drain and charging issues immediately after update. I hope more people keep sharing their stories.
Also there was a video on YouTube about watches and when Apple says it’s a battery issue but might not be, look for it and try the steps if you’re considering repairing or replacing.
So far, since the update people have complained from series 2(me) through series 5 about the same issues after the update.