I would emphasize this: worrying about the next bubble bursting is a distraction, like following the shiny. It is good you are asking the question, but the right plan to be making- a career plan- is what is important, and whether there is a bubble or not is kind of irrelevant.

Internalizing that can be the best thing any developer does. It is way more impressive to talk about all the skills you have acquired in your career in an interview than it is to talk about how your last company crashed and burned and you rode it right into the ground.

Make your plans for how you want to advance your career, what you want to learn, what field you want to work in, the companies that are places where you could pick up relevant skills. And plan for things you could do in the down time between jobs.