There is a pretty much perfect workaround.

Set Night Shift to "Scheduled"

Tap on the "From/To" menu, from there select "Custom Schedule"

Pick a time when you will almost never be using your phone, in this case using 4am as an example:

"Turn On": 4:00 AM "Turn Off" 3:59 AM

It's a shame there isn't a setting for it, but this works just as well.