From this post, I got the idea to remove and replace the wheels altogether using a hacksaw.
Here’s what it looks like right now. My problem now is that I can’t remove the leftover metal shaft from the caster wheel.
I’ve tried using some lubricant and hammering it with a screwdriver but it didn’t budge.
I would expect that the wheel shaft has a flange or maybe some knurling on it to prevent it from coming loose. You will probably need to drill it out. I wish you the best of luck on your journey, you will learn a lot about how things are made. I also expect that this will end with you buying a new castor or a new suitcase.