I need to make a correction above.
The 40uA I mentioned is the Light Sleep current on an MG24 when built with the Simplicity Studio development tools.
The correct current for the MG24 with (Arduino) Deep Sleep is ~1.0uA
I have just checked your code and it runs at 4.7mA and sleeps at ~1.05uA on a standalone XIAO MG24 Sense.