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This! I can say that it works, that games are being published with it, and it actually seems to be an easier preparation and submission process than the other console platforms. Other than that... NDA.
All Switch developers are under an NDA, so this "please share your experience" request is a non-starter. Instead, you should try out Switch releases of games from developers known to use GMS 2 and see if the export is any good from there. If there are major issues with the export, the answer is always in the pudding.