I found this answer on a similar post 4 years ago by the user oosyrag:
"Tile sizes can't be changed with actions, although the width and height of the entire tilemap can change.
If you want different "resolutions" of tilemaps, one way is to have multiple tilemaps with different tile sizes layered on top of each other and only display the relevant one at any given time."
I hope this helps or that another option exists ;-;