Hi there's a possibility to activate cheats retrospectively (i.e. Not playing in the lan) but permanently
Stay healthy
Not in multiplayer mode. Would be real kagge.
In single player?
Without Lan it won't be anything. But where's the problem? Every time the world starts, open it briefly in the LAN and it is good.
Open this website: https://irath96.github.io/webNBT/
Drag and drop the level.dat file of your world into the website
search for allowCommands and change the 0 to 1 by double clicking on it
load the file above with save again and replace the old level.dat file
Why not