I'm confident that OP has legal recourse against the seller with the expert testimony of their new inspection stating that it was covered up before the sale.

And they will likely get $0. Most of what they describe won't "prove" the prior owners had knowledge or covered up. Placing brick/mulch around before a sale isn't actionable as a cover up.

covered up issues like throwing down mulch over damaged wood and brick where water floods in

Ok, mulch can easily be moved and looked under during an inspection. Just like a rug. Same with bricks, you lift one up and inspect quick. I don't see you winning this claim.

We had to demo and redo the entire kitchen due to a water leak from the fridge that was a slow leak for years

Nothing you have is proof they were aware of this issue. You were not aware of this issue right away, it took 2 years to become aware (well longer than 30 days when you moved in).

Then a second damage in the fireplace dripping rain water

Again, no proof that they "knew" it was leaking.

Now a third flooding from the crawl space

Again, no proof that they "knew" it was leaking.

And this won't go far in court:

From new inspections we’ve been told the old owners definitely rigged things and it’s obvious how terrible the damage was for years.

That would be on you, you had full rights to inspect and if the rigging was so obvious then your inspector missed and you missed.

Welcome to home ownership, this isn't a case you will win.