Advice for someone who wants to become a professional photographer? I have several thoughts on this topic.
For someone to pursue this as a career, this has to be your passion. If you have not developed a passion for photography and the images you can create this is the wrong field to enter. I have been a shooter for 50 years and my excitement for the image is as strong today as the day I shot my first roll of film. I would say it is an obsession for me.
Get an education. It gives you a way to earn money as you build your business and it will open your eyes and brain to the world around you. Plus, learn how to operate a camera. The camera is a tool and like any tool you have to know how to use it correctly.
Become a student of photography. Look at the work of other photographers, especially the big hitters in this industry. Study their images and learn what makes their images timeless. I still read books on photography and will always be learning. In fact, every time I pick up my camera, I say I'm going to practice making images.
I could write a book to answer this question, but these are the most important that stick in my mind.
My enjoyment is seeing the image I create and knowing I have captured a moment in time that meant something to me.
Speaking about gear. To get started, I recommend an entry level DSLR or mirrorless camera. This will allow you to explore photography without a major cash investment. Eventually, as you improve and begin shooting for money, you will need to invest in high-end "pro" gear.