I'd say it's a bit of both. You can build yourself up and find such work in companies which have it. Not switching employers very frequently helps, because building credibility takes time.

After you've built up credibility in some interesting tech, other companies would find you based on your work.

This is just my observation, so take it with a grain of salt

You either need to find something adjacent to what you already do, or you need to build trust where you work and jump on any opportunities that come up. You can get noticed for work by giving conferences talks or being active on the right mailing lists or getting to know the right people.

In my career I built trust internally and so got interesting work. I talked about that work and so got approached about other jobs, and I’ve been able to move when I’ve wanted to because I’ve kept in contact with some former colleagues.

I would however like to stress that the most important point of this is doing the aork, and doing it well. If you don’t do that then everything else is pointless.