I have a recommendation for you since you are looking for dropshipping suppliers in the athleisure category that ship from the US. Have you heard of Spocket? Spocket is a platform that has a variety of different products that are able to ship to the US, with many in the athleisure category.
Here are a few benefits of Spocket:
Spocket offers a free trial, so if you want to try out all these features risk-free, follow the link here! I recommend taking a look at Lime Milo, they’re a supplier that ships from the US and have a huge library of athleisure style products!