Last I checked the highest quality widely used translator was deepl.com which is a commercial service that lets you translate only small snippets for free. To do larger ones you can upload them as pdf's, which increases the size limits.

I've been using the local translator built into Firefox and it's better than nothing, but it's pretty rough compared to either google or DeepL.

I don't think Kagi has its own translation service. They resell someone else's.

For simple things, the local translation in Firefox has been more than enough. Go to about:translations. It’s pretty limited compared to Google’s frankly impressive language list but I’ve used it almost exclusively since it’s added the languages I need to translate most frequently.

Came across this last night

https://github.com/niedev/RTranslator

Lemmy community is awesome

Libretranslate it's self-hostable, too, if you're into that sort of thing

The most private translation program is one that is completely offline.
With Mozilla recently adding offline translation to Firefox people are able to incorporate it in separate programs like https://flathub.org/en/apps/dev.ters.LocalTranslate

You can try this: https://private.mt/

https://translate.kagi.com/

I have found this one it is offline, no internet and for android.

https://github.com/DavidVentura/offline-translator

This is offline Text and image translation. And available on F-Droid.