We can't think of any reasons why Nintendo shouldn't include VRR support on its next Switch console. Performance upgrades are inevitable, but omitting FreeSync or G-Sync would be a huge oversight on their part.
https://www.notebookcheck.net/The-next-generation-Nintendo-Switch-absolutely-needs-this-one-feature-that-the-Playstation-5-has-yet-to-receive.553591.0.html