3. There is a Blueprint on the Developer Center to prevent users from placing an outbound call not On Behalf of Queue https://developer.genesys.cloud/blueprints/terminate-voice-calls-with-no-queue/
It shows how to set up v2.detail.events.conversation.{id}.user.start for that scenario using one or two conditions (depending on what numbers you want to allow users to call without a queue associated). Directions are at the bottom of the page, in case you want to look at that for extra ideas.
------------------------------
George Ganahl GCCX-AI, GCP, GCSME
Technical Adoption Champion
Genesys
2024 Community Member of the Year
------------------------------