When setting up an Automation to assign issue to active sprint upon issue creation, I can't find and select the actual sprint for our Next Gen project in the drop-down list at all.
The list only displays all sprints across the board for projects setup using older/current Jira.
As you can see in the screenshot, our Jira is full of several projects each containing many different sprints BUT our only Next Gen project (sprint) we we wish to use does not exist in this list at all 
Just to note, I've tested the automation and it works perfectly (I tested by selecting any sprint from another project). So the issue is literally just being able to choose the correct sprint for the Project this automation is only being created for.