I use an app called Relax Melodies at night — they have nice breathing exercise relaxation tracks, and you can pick and choose the sounds you layer underneath. I have lots of nature sounds with underlying “vague melody but it repeats, with enough minor variations so you don’t get sick of it but it fills the background.” They have all kinds, though, including city noise (yuck). I think there’s still a free version, but I liked it enough to buy it, because the “white noise” is so customizable. Maybe worth a try?