My recommendation is this: add the Field that you want to be “Conditionally Required” to your Field Editor, TWICE. Setup both fields exactly the same, but have one be Required, one NOT be required. Then add Rendering Conditions to each so that the “Required” version of the field only shows up when you want it to, otherwise the “non-required” version of the field shows up.
So you want “State” to be required, but only if Country has specific values. So add the State field to your Field Editor TWICE.
First State field – mark as REQUIRED: Conditionally Render this field so that it only appears if Country = “US”
2nd State field – Do NOT mark as Required: Conditionally Render this field so that it only appears if Country != “US”
