iwatch series 5 battery drain

i have had iwatch 5 since December 2019. i charge it to 100% at 7pm, then put on around 9 pm and wear to bed, one or 2 workouts recorded, and usually have 35%-50% battery life. Started noticing a decline in battery life, with no change to settings. i have tried everything-in fact, Apple support ran me through all the steps, then sent my watch in for repair, and they sent another watch.  First day with new watch, and at 3 pm, already at 33%.  It has to be a software bug but i dont know where else to look. tried all the suggestions here for iphone battery life on my iphone too. i have iphone 11.  my watch runs minimal apps already. any suggestions?