Search for properties in custom objects

We have created user-defined objects (contracts) and would like to define criteria for a search in the properties. However, this is only possible with standardized objects (contacts, companies …). An adjustment would be great.

retracted

It is possible, but you would have to mark these properties searchable via API.
Example:

"searchableProperties": [
 "address",
 "city",
 "project"
],

Being able to use the properties interface to do this would be a great improvement.