Hello @Legenfde and welcome to the forum!
For my understanding, Krita already has an infinite canvas, but most users do not discover it due to the fact that they never scroll the canvas to the stop-dog. If they did, no matter in which direction, they would discover little arrow symbols, and these arrows would expand your canvas in that direction.
This is an action that you can repeat as long as your RAM allows it, so, the more resources your device offers, the bigger the possible canvas.
Michelist