We shuffle everything but only add 5000 to the queue.
Is there any practical reason why you’d want more? If you had 20000 tracks, you’ll get a random 5000. Same as if you added all 20000 shuffled and listened to the first 5000 or fewer. There are technical reasons we limit this, but it really shouldn’t matter. If you have any reasons (beyond “just because”), I’m willing to hear them.