If you live in the Dallas area you have to try Fat Straws - I just love that place! I was becoming a regular there for awhile where they knew my name - they are just so yummy!
The tapioca balls are vegan and gluten free! Yum! I tend to get the regular brew (lower calories), but they do have plant-based milk teas and I will order one of those as a splurge. The staff is very knowledgeable and will tell you plant-based/vegan options! Make sure you bring a wide mouth reusable straw! I got some on Amazon and they even sell them with the pointy end specifically poke through that top wrapper.
I "think" you can bring your own mason jar/reusable cup now too - I am always doing my part to save the earth and you should too!