This problem only seems to have gotten worse over time, but the current state of the Switch version of the game is "barely functional".

• Start a new game
• Leave all game settings at their default values
• Walk / run anywhere for more than 2 or 3 seconds
• Game is no longer able to keep up with chunk loading

Does not matter if you are playing survival or creative, though any faster than running movement (boat travel on water, creative flight, etc.) will show the problem even sooner.