I found two great android white noise apps that are free and very customizable
Atmosphere and White Noise Baby Sleep
I have a great WN app as well, but I don’t want to be woken by every notification chime throughout the night and I keep my phone charging in the next room so I can hear an emergency call but not every notification. Apps are great, but not for everyone. There’s also the Alexa or Google smart speakers, but Wi-Fi can be wonky at times. White Noise suddenly stopping in the middle of the night jars me awake just like a loud noise. So this may not sound as good or have the options you can get from an app, but I think it is good enough and above all, reliable.
I have a different white noise generator as a backup and for trips, but I really like Ambient Noise skill on Alexa.