Hi Emma,
Thank you for reaching out, and apologies for the inconvenience.
Filtering with both single-reference and multi-reference fields is already supported. I have rechecked this on the latest version, and it is working correctly on our end.
If the feature is not working on your site, there may be a configuration-related or environment-specific issue causing the problem. To investigate this further, could you please share your site administrator access with us? That will allow us to check the setup directly and identify what is preventing the feature from working properly.
We look forward to your reply.
Best regards