2.8 is nothing more then a low budget demo of what KH3 could be similar to the FFXV Episode Duscae that came with Type-0 HD.
If FFXV is any example, then it the actual game will end up looking and performing much better. Episode Duscae for example ran at 900p on PS4(main game 1080p at release) 720p on Xbox One(main game 900p at release) and could almost never hit 30 fps(main game rarely drops from 30 fps but has some frame pacing issues).
KH3 will likely end up being far more graphically intense and optimized better.
I dunno why KH3 keeps being brought up in this thread, until proven otherwise expecting any AAA PS4/XB1 ports to the Switch is a pipe dream.