I'm getting really good battery time on my new Ultra. I just received it on July 24 and was going to do a restore from my Watch6 Classic, but after reading this thread I decided literally at the last second (as I was going through the setup) to do a manual setup.
Tuesday I went through a decent amount of battery doing setup on the watch , customizing my watch face and just plain messing with my new toy.
On Wednesday I charged the watch to 100% at about 8 in the morning. Last night at about 10pm I had 85 % battery left. I charged the watch to 100 and put it on about 10:30 pm since I wear the watch at night for sleep tracking. At 8 am I checked my watch and I had 93 % charge left. I charged back up to 100 for the day and wore th watch all day until about around 10 or 10:15 pm and checked the charge left and it was at 85% after wearing the watch from about 8am until 10 or 10:15pm.
I don't use AOD and I don't use LTE. I only use Bluetooth since I always have my phone (S24U) with me.
You might want to consider doing a full reset and doing a manual setup. It might work and it might not but I'm having great battery life with my new Watch Ultra.
Good luck getting the issue fixed!