Provably fair can only prove that your roll has not been tampered with.

There are many ways that provably "fair" systems can be stacked before your roll has ever begun.

https://www.pcgamer.com/man-steals-pokemon-cards-on-the-job-in-largest-theft-the-game-has-ever-seen-tries-to-sell-his-haul-but-the-law-is-super-effective/

This can be an example of that.

Let's assume you can verify the contents of the pack by a code on the pack but let's say it is hashed with a seed and the seed will be revealed x amounts of time later so you can't go around and verify the contents of unopened packs.

If the card stealing happens before cards go into a pack and the code generation, you'll be none the wiser that your packs got tampered with, since you could verify the contents of the pack and see that they match with what you got.

In your comment, you said you would like to introduce hive blocks as a third party for HoloZing vials.

I mean this could also be manipulated in a different way.

You would know the signature of the block for 3 seconds, you would know the seed of the server. Hence you would know the rolls for those 3 seconds and decide to open your vial at the time that will give you a good result. (I am not saying you would, just an example.)

Another way is to give yourself a good outcome and generate the provably fair info after the fact.

You can then go and give that info to people saying look here is the proof of my roll.

For a provably fair system to work, at least in the way you want it to work. All parts of the seed that gets generated need to be unknowable. The problem then becomes how you prove that you don't know the server seed.

Now people need to trust that you don't know the server seed.

In casinos provably fair system works because it is all about ensuring your roll has not been tampered with, you're not concerned with what other's are rolling.