How to save empty decimal admin form field not as 0.00 but as null in database?

Question

I have an Admin Grid with one column named min_weight. This column has the datatype decimal (5,2) in the database. The default value for the column is NULL. If I try to save an entry with the Admin form, Magento always fills the empty column with 0.00. But I would like to have the value NULL in the database not 0.00. Is there a way to stop Magento 2 from formatting the column value as 0.00?

This is the field configuration in the form.xml:

<field name="min_weight" formElement="input">
 <argument name="data" xsi:type="array">
  <item name="config" xsi:type="array">
   <item name="source" xsi:type="string">zones</item>
  </item>
 </argument>
 <settings>
  <dataType>text</dataType>
  <label translate="true">Min. Weight</label>
  <dataScope>min_weight</dataScope>
  <validation>
   <rule name="required-entry" xsi:type="boolean">false</rule>
  </validation>
 </settings>
</field>

The form data that is submitted when pressing the save button contains an empty value for this attribute (which is correct):

items[985][name]: test
items[985][min_weight]

But Magento 2 writes this empty value with 0.00 in the database.

The problem exists regardless of whether I modify the record via inline editing or on the Edit page, or create a new record.

I would be very thankful for any advice!