Hi,
I had the exact same problem as you on my Galaxy S10+ (One UI-Version 3.1, Android-Version 11). I couldn't find the "Energie Saving Mode" when I created an Bixby Routine manually, I also had to modify the "Nighttime battery saving". Then I saw a notifaction on that routine, explaining: "Execution of this action is not possible. This routine could not perform this action because adaptive power saving was enabled." Then I turned off the adaptive power saving on my smartphone and afterwards I could find the Energie Saving Mode when creating a Bixby Routine manually... I seems that Bixby Routines is only displaying options/functions, that are currently possible.
