This sort of thing: https://coffitivity.com
But local first, app, using sounds curated to avoid engaging language center or triggering startle reflex.
FWIW, happy owner of TMSOFT's "White Noise" on iOS for nearly 20 years, which isn't scammy. Particularly enjoy how easy it makes it to capture and loop ambient environments. But still looking for an app with the perfect background cafe/office loop for focused work.
(I also really like: https://ozlosleep.com This is the successor to Bose's sleep buds, the literal tech bought back by engineers to make a go of, and works better.)