Unless it offers the option to switch saves back and forth between the OG one and the Lite, I don’t see myself getting one. That’s one thing I liked about having two Xbox Ones, with cloud saves being useable on both of them.
As for no TV mode, while it may be disappointing to some, I wouldn’t put it past people figuring out a way to get TV mode working anyway depending assuming it’s not an outright hardware limitation preventing it. A software limitation could be overcome by the right people.
If you have a Nintendo Online Subscription, your backups should be able to transfer over.