Thank you for the additional information.
The upcoming Wear OS 5 release is supposed to include new battery optimizations to improve overall battery life.
I have disabled features that I like for the sake of extending battery life. I turned off 'Raise wrist to wake' & vibrations for notifications & calls. I also turned off the gestures. They didn't work consistently very well for me.
Other steps I took was to:
○ uninstall apps I didn't use
○ turn down screen brightness
○ use dark background watch faces.
○ look for watchface developers who optimize their faces. ('Amoledwatchfaces' make battery friendly faces.)
○ turn off app notifications that I don't really need to appear on my watch.
○ I also did #1 & #3 on your list.
You can check your app usage through the Wearable App. Go to Watch Settings / Battery and device care . Then tap 'Battery' & you can see what apps are using your battery. I read the Whatsapp uses a lot of battery, however, I don't have any personal experience with it. Hopefully, things improve before you enable LTE.