Is it possible to have the start of the rental to be only within 4 days from the moment of booking, but without restrictions for the end of the rental?

Yes, this can be configured.

1. Copy the rule and open its settings.
2. Uncheck the Show in the legend option.
3. Check the Shift end from the current moment option, enter 4 days, and save your changes.

4. Add a reaction.
5. Select the Error type and enter a message explaining the 4-day booking restriction.
6. Enable the Enabled in all rules option.

Enable this reaction only for the original rule.

As a result, when a customer books a time that overlaps both rules, the reaction will not be triggered. However, if they book only within the original rule (for example, from the 5th to the 10th day from the current moment), an error message will be displayed.

See an example in action: