Casual reminder that it's more than three years since they started building this thing. On flat land. Next to an access road. And its only interaction with the rest of the park is the pass over the railroad.
Is it really such a complex project to warrant taking this long to build? I mean, they started installing track in May 2019. By comparison, Velocicoaster only went vertical in early 2020, and the coaster was open in April the following year. Hagrid's Motorbike Marketing Buzzwords began construction in January 2018 and was open by May the next year. Both of these, but Velocicoaster in particular, were built on much more challenging sites.
Then again, I presume Disney is deliberately taking it a bit slow, because they can afford to when the project is so far out of the way (Universal, by comparison, can't keep a construction site in the middle of their park forever). It's not like Magic Kingdom particularly needs to hurry either, as it keeps printing money despite not getting new attractions very often. If my skimming of the Wikipedia article is correct, the park last received an attraction of this scale in 2014 (Seven Dwarves Mine Train), then in 2012 (Little Mermaid), and the time before that was 1992 with Splash Mountain - a few attraction updates notwithstanding. They can build one ride per decade and still be the most visited park in the world.