Aren't they still there, just different method of enabling?
Long press the power saving icon on the notifications panel/quick actions to get to the Power saving mode menu.
Turn it on for "normal" power saving (tweaking the options below).
Turn on "Limit apps and Home screen" before turning on power saving mode, for the previous extreme option.
Ah I see, bixby routines only gives the option to turn on/off power saving mode, so if you don't have the "Limit apps and home screen" option enabled, then bixby routines won't do anything with that.
Send it as feedback on the Members app.