Use 'Do a search for...' when creating/updating a record's relationships

Currently, if you have been on a navigation path, or have created a form, you can create or edit a relationship in an action. That relationship allows you to choose an input’s value or a current navigation path’s ‘thing’.
It would be great to be able to choose a specific collection entry to link to, however.
This might be so with a category:
“Do a search for…” > “Categories” [filter: name = ‘posts’, first item]
This will add the entry to the posts category without the need for a navigation path or a dropdown (eg, not necessarily giving any user the choice).

I imagine this will be particularly helpful when Custom Actions come in, so that information from the database can be used in those actions.

Currently the workaround for this is to create a list of whatever you want to achieve (here, categories), filter that list (only show the first category matching ‘posts’) and then you can use the list’s category as the one you want to use.
NB - at present, if you choose to do this, the ‘standard’ pre-made form will not validate required fields.

It may also be possible to achieve this kind of result using ‘Manual Data’ as a “Reference” or “Collection” item, but I haven’t quite worked this out.