Is USDT safe after what happened to UST?

So unfortunately I had some UST and since I'm not really a crypto expert, I just couldn't foresee that it's possible that a "stable coin" loses 40% of its value or vanishes into thin air.

So this morning I woke up, saw that UST has collapsed (even touched $0.68!) and decided to convert my UST to USDT ($0.9 per UST).

Now I'm just wondering should I convert it to good old cash? is it possible that such a thing happens to USDT too? I mean this whole ecosystem is so volatile and fucked up to be honest.