You actually always have an XNET database. It's just a matter of whether you use an external database or whether you create objects on the fly.
From your screenshot, it looks like you are creating objects on the fly using the in memory database.
Looking at your frame configuration, I was surprised to see Remote frames being configured. Most devices that I've encountered don't use them.
So what sort of session are you trying to create? Frame Out Stream does not allow for cyclic transmission. You can repeat transmissions using a software loop. If you really have cyclic frames, Frame Out Single Point or Frame Out Queued would work. The post you referred to earlier was using the Frame Out Single Point.
The XNET help is actually pretty good about breaking down the session modes. From that help, "... this mode does not repeat its transmit. Unlike the Frame Output Queued mode, the Frame Output
Stream mode does not use CAN frame properties from the database."
So if you're using this mode and getting unexpected delays, it's likely due to your sequencing.