Why do my cards not appear in random order?

I have a downloaded deck with multiple subdecks. I have the cards set to random intervals, but they appear not in random order in their individual subdecks during review. I just want all the cards in the entire deck to appear randomly. Thanks

You can use these options, for new and review cards:

This requires the v3 scheduler: The 2021 scheduler - Frequently Asked Questions

For fully random, I’d also recommend adjusting the gather order instead of the sort order.