A patent filed by Nintendo has offered up a potential clue as to what a possible Switch successor could offer in terms of features. The patent describes an "information processing method" that would allow owners of a Switch 2 or Switch Pro to appropriately switch from one game to another like Xbox Series X users can with the Quick Resume feature.
https://www.notebookcheck.net/Nintendo-Switch-successor-may-offer-Xbox-Series-X-like-quick-resume-feature.568160.0.html