Well as people have been saying for months, Tether is crap, and the entire price of all crypto is traded in Tether, which just happens to have a CAP of $63Billion USD, but only has $2B of real assets ( aka cash )
So right now they just lost $3B ( now $60B ) that means if the first to leave already got their 'cash', then there is no cash left for the bag-holders ( HODLer's )
There was always a lot of speculation and discussions going on about Tether since 2019 when they changed their wording from "every USDT is backed by a real USD" to "we have enough reserves to back every USDT with a real USD". I think that this change of wording really is a reason to be worried because the audits that bitfinex as the parent company of tether is presenting to prove that every USDT is still back 1:1 by a real dollar are not living up to traditional auditing standards.
What you are saying though that they only have 2B$ worth of assets but have 63B$ worth of UDST circulating would be extremly worrying if these would really turn out to be true.
I also switched from using USDT to USDC a while ago.