Add between() method to QueryInterface
The extbase Query objects supports between() for some time now. But it doesn't appear in code completion when writing code in an extbase repository, because QueryInterface itself does not define between(). I see no reason why it shouldn't be there.
Adding the method to the QueryInterface could possibly break classes, that implement the interface. In TYPO3 core only the Query object implements QueryInterface.
There might be third party code using that interface, so this should probably done for TYPO3 11?