I have traded both BTC/USDT and also altcoin/USDT pairs on futures and from my experience it is safer to stick with BTC/USDT futures trading. Although not as profitable as some alt pairs in the short run but with a good trading strategy and patience, it is much more profitable to use BTC/USDT pairs for trading futures. One of the worst Altcoins to use for futures trading are the meme coins. Now I stick with BTC.