Just arrived and display won't power on

If you heard different sizes called U.FL, that was just wrong. Other sizes are different series, like W.FL, E.FL, etc. Hirose has a ton. And each has a defined receptacle size. They do have the same general appearance, but that doesn’t make them all U.FL.

But more on topic, when Framework lists their cables a U.FL, I trust they are either actual Hirose U.FL or a fully compatible connector, which Hirose does define as using a 2mm in diameter receptacle.