Glad you have it working now, @cooperativeventure! If you have suggestions to improve documentation or functionality, please let us know. We agree this is not very intuitive and I've written a little on the topic at Missing Entity ID with form that can create or update Entities - #3 by LN
This helped us identify a bug, thank you! Although we recommend using explicit non-overlapping condition, our intent was to do an "upsert" (create if new, update if existing) in that case. We will fix this in v2026.3. In the mean time, the fix is to make sure your conditions don't overlap.