Hi @timtprc,
The best place for these kinds of requests would be the HubSpot Ideas section of the community: https://community.hubspot.com/t5/HubSpot-Ideas/idb-p/HubSpot_Ideas
These requests submitted to the HubSpot Ideas section of the community are reviewed by the HubSpot product team, based on their popularity and the assumed demand
For now, the best workaround would be via list membership:
It takes a few more steps but will get you there as well. In your list, click ‘Add filter’, then change the ‘Filtering on’ dropdown to the desired associated object. Save the list and reference it in a fit or a combined fit/engagement score.
Have a great day!