It depends on the progression of certain areas. USH announced the WWOHP in 2011. To make room, the Universal Amphitheatre was torn down in late September 2013, construction immediately began shortly. It opened almost three years later. SNW was announced in 2015, USH didn't start doing that until 2018, and it's been almost four years due to building in a small area (compared to the WWOHP) between the employee parking lot and panda express, as well as some soundstages in front.
The blue parts just got started a month or two and it's almost January 2022, so they have a long way to go because the area outside the Bowser Castle/Princess Peach castle doesn't seem to be finished. If we see the area being rapidly progressed so much by spring 2022, then maybe we might see a summer opening. If not, then expect Winter 2022 or early 2023 to be the best possible dates. USH hasn't announced an actual SNW opening date nor advertised it as of December 12, 2021.