Yesterday Apple released iOS 15.4 beta 1 to developers, with the ability to set up Face ID to recognize a masked face. The feature can recognize the user's "unique facial features around the eyes". In addition, in the settings there is an item "Add glasses", which allows the owner to unlock the iPhone while remaining in the mask and glasses at the same time. To use the new option, you must rescan your face.
The developers warn, that Face ID will not work when wearing sunglasses. Currently, the ability to unlock iPhone using Face ID without removing the mask is only available on iPhone 12 and 13 models.