Futo has two models. The default is the small, fast, less accurate one. The other is bigger, slower, and more accurate. In english, at least, it's working flawlessly for me.
Futo.org is the place to get the .apk. Note that they are also developing Grayjay.
Futo asks for network access only to (1) download models and (2) take donations. Once you've done that, you can turn it off. Please make a small donation. These are worthwhile projects.
PS. Note that whisper, which FUTO is based on, is also available for lap/desktop. That has even larger, slower, more accurate models:
pip install -U openai-whisper