🧐 Your opinion needed. Automations in Fibery (limitations and opportunities)

I realise now that I misunderstood this line

as meaning that you wanted to apply filtering to the dropdown box of options that appears when linking items, but I guess now it was about ‘creating a lookup collection field with filtering’.

No, you’re right, formulas (and lookups) do not behave like ‘normal’ relation views, so if that’s essential, then your options are somewhat limited.
But we do have that in our backlog to address:

Alternatively, your issue would possibly be solved by this: