Its so sad how its come to this but I'm glad people are starting to take their privacy and expectations of apps on their device seriously. I have an app that has "all the sounds" on device and yet, still requires internet. Sad!

Is it for recorded audio or live audio? For recorded, Audacity can remove basic noise profiles. For proper, advanced audio editing, you'll need to use something like the Edison plugin in FL Studio; or a similar process in a DAW of your choice.

The AI options just take all of the work out and make the process easier at the cost of quality and privacy.

You could install Audacity and use their noise reduction feature.

https://github.com/xiph/rnnoise

I have 2 options for you, but you need to ... ahhmm ... block then from internet.

Accusonus ERA Noise Remover GOYO ( This needs a relatively powerful PC )