Many sleep audio websites do indeed have several common pain points:

Too many ads: I get interrupted by pop-ups and countdown ads after listening for a short while, which makes me more and more anxious.

The audio is not pure enough: in pursuit of "special effects", too many human voices, music or high-frequency noise are mixed in, which interferes with the actual desire to help sleep.

Playback is unstable: it stops when switching pages, cannot loop, and loads slowly.

Too complicated: When you really want to sleep, you want to operate as little as possible, but many platforms are designed to be "control consoles".

I later discovered a website for brown noise sleep:

Clean, continuous brown noise: All audio is processed and looped seamlessly, without any abrupt breaks in the loop transitions.

No ad interference: The entire site is clean, and there won't be anything that suddenly wakes you up.

Minimalist design: It plays automatically when you open it; there's no need to search for buttons or register an account.

Sleep-specific functions: It has a timer and a black screen mode, truly designed for sleep scenarios, rather than just piling on additional features.

If you're picky about sleep noise, or already fed up with ads and complicated interfaces on other platforms, you might want to try this site:

https://www.sleepbrownnoise.com/Brown-Noise-Library/super-deep-smoothed-brown-noise-for-sleep