I think the screenshot shows the Insert date / time dialog rather than the Create event dialog.
Those are two different workflows in Discourse Calendar:
Insert date / time is used for replies in a topic whose OP contains a [calendar] block.
Create event creates an actual Event ([event ...][/event]) and is where the recurring Event settings, including the recurrence end date, are available.
So for the feature announced in this topic, try opening the composer + menu and choosing Create event, rather than Insert date / time.
I was testing that recurring Event flow recently and also found an edge case after a bounded recurrence has completely expired, which I’ve opened a fix for here: