I am attempting to make a gamebook-style story with a custom name. However, I find the console annoying and unnecessary because I only need it for the start of the game.

Does anyone have a good solution?

Try

JS.uiHide("#txtCommandDiv")

to show it again:

JS.uiShow("#txtCommandDiv")

Worth noting that it will change back to default visibility when the player loads a saved game.

If you want it to be hidden for most of the game, you should have a script to hide it in the "UI Initialisation Script", on the game's "Advanced Scripts" tab (if you're turning it on and off, you would need to have that script check where the player is or similar first)