How to implement filtering using point + range

I couldn't find this in the spec (part 1 or 3) or in an earlier issue, apologies if I overlooked something.

Is there a way to implement a filter where the client sends a POINT geometry in the request and the server returns all features within a certain range of this POINT? The range could be e.g. a kilometer, in the case I'm asking about this is fixed on the server, the client cannot ask for a specific range.

It seems to me this is a common thing for users to want. Quoting the SDW-BP:

Support queries for Spatial Things based on user needs. For spatial data, typical needs that should be considered are neighborhood searches (e.g., "what is near me?" or "what is near this Spatial Thing?")

Review the filtering requirements in specification parts 1 and 3 and compare them with the SDW-BP neighborhood-search guidance. Determine whether a POINT-plus-fixed-range query is already expressible; if not, define the API behavior needed and how the result will be documented and validated.