What do I do now so that when the platform doesn't work, I still can?
Now the answer is obvious: you don't need to stop using platforms, you need to stop being dependent on any given platform.
Store all your videos in two different storage providers, plus your house archive. Have accounts on at least two different video distribution systems. Get people interested in seeing your own website regularly, so they don't just subscribe on one platform and ignore you otherwise. Get them engaged in several communities. Occasionally put special bits on just one of those video distributors, and then add them to the other(s) later. Get people used to following you.
This is, obviously, more work than just shoving everything to a Youtube channel, or just posting to Medium, or just hosting with Wordpress -- but the point is that when one of them folds, has a service disruption, declines your credit card, or is invaded by leet script kidz, your business survives and merely suffers from hiccups while you re-point things.