The rx1_delay setting will be reflected in the scheduled tmst of the gateway transmission.
For OTAA devices the rx1 delay is sent in the join accept. For ABP devices it shouls be configures to the correct out of band, the CS and device delay need to be in sync to have a successful downlink.
The CS expects the gateway to queue the packet until the time to transmit. Additional metadata not shown in the UI is sent with the packet dr, freq and payload.