How do you find what you're passionate about?

I feel like I’m stuck in a rut and I have nothing that I’m passionate about.

I want to find a job where I feel fulfilled or at least a hobby that I get actively excited to do. Maybe start my own company based on the above.

But I have no idea how to find that “thing”.

When I was a teenager, I had a ton of excitement about specific things and the energy to go learn every little thing about them, but now in my 30s, even if I know I’m interested in a subject, I barely pursue the topic.

It’s like there’s a wall of apathy between the thing I might be interested in and the act of following it.

I’m not depressed. I have an active social and dating life, I eat well, sleep well, have a good relationship with my family.

But the spark and passion that I felt maybe 10 years ago is gone.

How do I rediscover and do something with that?

Is this just part of getting older / the human experience?