Simply do not own any USDT. Nobody can guide you here as we are sailing the most remote crypto market areas: we have never been here before but remembering history I can clearly see that if something happens to Tether, the whole market will be affected.
Owning bitcoin is much safer on the long run, because if USDT dies BTC will certainly survive.
How can I be so sure? Just look at what happened in the past.

There are millions of cryptocurrency users out there, who think that Bitcoin is a bit overpriced right now. They believe that a major correction can take place sometime soon, and the exchange rates can go down by a large amount. These are the people who still own USDT, and we can't really blame them. But then, USDT is just a token issued by the Bitfinex exchange, and it is not as secure as Bitcoin. Cryptocurrency exchanges get hacked and go down all the time, and Bitfinex is not 100% immune from such incidents.