It was already rumored that at least one device in the upcoming OnePlus 7 series would feature fast UFS 3.0 storage, but now it has been confirmed by CEO Pete Lau himself that the regular OnePlus 7 smartphone and the Pro and Pro 5G variants will have this storage solution. The Samsung Galaxy Fold was going to be the first device to bring UFS 3.0 to the mass market until it was recalled.
https://www.notebookcheck.net/OnePlus-7-gets-one-over-the-Samsung-Galaxy-Fold-with-UFS-3-0-confirmation.420172.0.html