Don't even worry about all the negatives that are thrown around. I paid 0 attention to all the "but there's so much competition", "I'll never be found with over 5+ million items", and "it's too saturated, I can't do that" mess. People have been saying those things since the beginning of time, and yet new fabulous business sprout up everyday. If you are good at it (and you're willing to work for it), you'll attract attention. My shop was slow to start because I was thinking, "what can I make that will be popular on etsy?" when I should've asked myself, "what am I passionate about? how can I fit that into my shop/brand?"
But also, I didn't just magically have products that sold. I opened my shop to sell prints. Literally 0 of those things are in my shop today. I poured my heart into so many things that didn't work. Posters, coasters, magnets, pottery, pendants, and stud earrings. Of those, the stud earrings are really the only thing that has worked for me. Just don't feel deflated when one thing doesn't work, wait around for a bit, and start something new. Eventually you'll find your niche.