Ability to Access Current Entity in Non-Automation Formula (for Purpose of Creating Lookup)

As I understand it currently, while it is possible to access the current entity fields when using a filter in an automation formula — i.e., a formula constructed for use in an action button or rule, where the current entity is referred to as the “Step 1” entity — there is no such ability to do this when constructing a non-automation formula.

Is there a reason why this is so? Is there a way that such functionality can be added for use in a non-automation formula?

(NOTE: I wish to use such functionality so as to create a lookup (via formula) to return a single entity rather than by having to link that entity via a relation.)

To the extent that such functionality is not currently possible, I suggest this as a new feature.

Any thoughts or suggestions are appreciated. Thank you!

Can you provide a concrete example of what you want to do. It might be possible.