Changing PIR Function After Sunset

The 5753L has a feature called Join Mode. found in the environment tab in the toolkit.
Assign the Outdoor sunset switch as your join mode group (assume you will use lighting as the join application)
When you do this, a message box appears, just let it do its job say yes to both popups
You will see key slots 5- 8 change to green and also show as multiple Groups
If you have a normal setup, then key 5 and key 6 will have the same function as you applied for the sensor
but show as multiple groups.
drop down the group for key 5 and key 6, and select your group for the bathroom night light,
for key 7 and 8, drop down the group and select as unused
Ensure the group for key 1 and 2 is your main bathroom lights

How this works, Daytime Sunset Switch sensor sets Sunset PIR group to Off, 5753L will run with keys 1 - 4 Functions
Sunset happens, and Sunset Switch sensor set PIR group to On, 5753 will now run keys 5-8

This is sort of like a profile change, but it has it limits, although i am moderately sure it will work for your scenario.
give it a try

 

HI, apologies the names you see here are the names given to the group address in my example, not units,

So the Join Group is just a Group Address on the Lighting Application.

So your external Sunset Switch Sensor is the one control the group that i called "Sunset PIR") this group i assume is Off when sun is up and On when sun is Down , what that group does is enables the key 1-4 mask when group is off, and key 5-8 mask when the group is on.