@juraj.masiar, what you described is essentially a first in first out queue, and yes, that’s the core of how the review queue works: older items are processed first, new items get added to the end of the queue.
But, I think you might be imagining this as a queue of submissions when it is more accurate to think of it as a queue of add-ons to review.
When a developer submits a new version for review, the extension gets added to the end of the review queue. Later, if the developer submits a new version while the extension is still queued, the extension’s queue record is updated to reference the newer version. The overall queue position remains the same, but the content being reviewed has changed. When the add-on is reviewed, it’s removed from the queue.