There is 3 good choices:
- DuckDuckGo AI is anonymous and quick to use.
- Proton Lumo is confidential (most private online service)
- NanoGPT is both cheap, anonymous and most powerful (in specific cases if you need highest precision)
I asked this question myself before here:
A lot of people recommended NanoGPT, so I started using it, its great service in many ways. You can learn in this post why. Proton Lumo did not exist yet back then.