In a strange turn of events, having started its first couple of weeks with serviceably-good-but-not-great battery life that would make it through a full day with just recharging during my morning routine, to the disastrous Cardiogram incident, battery life has been taking a northwards turn to a point where it hasn't been anywhere near 'low' when I would normally put it on its charger the past week. Having noticed that over a couple of days, I took my watch off the charger at 12am Tuesday morning. It's now nearly Noon on Wednesday - about 36 hours later - and I'm still sitting at 24% (and will be throwing it on the charger shortly).
My settings that I would anticipate to have some impact:
WiFi, BT, and LTE all enabled, ring/notificaton volume set to lowest audible level, haptics fully enabled, screen brightness set to 1 of 3, adaptive brightness on, sunlight boost off, screen timeout 15 seconds, always-on display off, tilt-to-wake off, touch-to-wake on.
I didn't place/receive any calls on the watch during that period, nor log any workouts/use any gps navigation, but did regularly check notifications/SMS, and used assistant several times.
The battery is the only aspect of this watch that had me concerned, and I'm feeling quite comfortable now that that anxiety can, at least for me, be fully set to rest.