-Probability of Tether ever collapsing is incredibly low-

Tether has nearly $50b of cash or cash equivalents.

Tether charges 0.1% on redemptions, and min size is 100k.

It would take $50b + $50M in redemptions before we find out if this "hole" exists or not.

-Commercial Paper backing Tether-

https://tether.to/en/transparency/#reports Currently Tether states their commercial paper exposure to be 0.07% That doesnt seem to be any significant amount.

Now you can complain that there has not been an audit. That's fair. There could be a hole. But most of the stuff you are saying makes no sense, and if there is a hole we will probably never know.