Conditional filters, first_notempty and zero values

I am using conditional filters to update a record with partial values using an API call (https://www.youtube.com/watch?v=WvOlaXmoq5o)

This is working as expected, but I am running into a problem when I attempt to update the record with a zero value. Where I am attempting to write a zero value, the associated field in Xano is not being updated. If I change first_notempty to first_notnull then the zero value gets written, but if I don't include the field in the payload the Xano field is cleared/reset to zero (which defeats the purpose of a partial update).

I am looking for a solution where in one API endpoint:

Zero values from the API call are written
Non-zero values from the API call are written
If fields are not sent as part of the API call, the existing values should persist

I am using WeWeb as my front-end.

Screenshots from Xano and WeWeb attached

WeWeb.png

Xano.png

Thanks in advance!