Shark-Man

im trying to make a swimming like square around the player, each time the player moves water surrounds him so i have 2 things i cant figure out
first heres the command 'execute at (player1) run fill ~5 ~5 ~5 ~-5 ~-5 ~-5' the first thing i want to know is how do i make the previous water disapear after player1 moves, 2nd how do i make it so that it doesnt fill existing blocks but just makes a shape around the blocks im version 1.20.1