It'll be much, much earlier than that. Universal has the mindset of opening things ASAP right now. Both JW and SLOP seemingly being fast-tracked. I'm getting the same vibes from Nintendo.
Here's a question that a friend thought up to me. What if Universal opened SNW in phases like Galaxy's Edge and Marvel Land. Meaning Mushroom Kingdom and Mario Kart in Phase 1, then Donkey Kong or whatever else they want for a 2nd attraction in Phase 2. I think this way we could see an early 2021 opening date for Phase 1 (since it's smaller than Japan's), and late 2021 or 2022 for whatever possible 2nd attraction? (if we get one)