yes I believe you have it right wrt tether soaking up a lot of UST demand. Tether is a beast, if you have Fountain FM app you might enjoy the recent Gold Goats 'n Guns interview with Caitlin Long, well maybe not that's pretty subjective, but in any case towards the end they discuss Tether is a business entity and its pretty interesting.

Try out the aqua wallet too, it is btc and usdt exclusively iirc.