I know that it's not what you're asking for, but I thought I'd chime in with a lateral solution. My wife and I live in an apartment building and neighbors can be pretty loud, plus I have rotating shift schedule so my sleep schedule slides drastically to support that. If the noisy environment is mostly outside, thick blackout curtains will also dampen a lot of sound. Otherwise, a fan will do a lot in terms of soothing white noise that also kinda masks other sounds. And finally, for the actual reason I started leaving this comment, there are pretty solid Bluetooth sleep masks that are designed to be comfortable and have battery that can last all night. My wife has one and it has really helped her out. You can also remove the electronics to wash the mask as needed.

Again, I know that this isn't what you were explicitly asking for, but it could solve your root concern all the same. Good luck!