The SimplyTranslate front end has many languages, translate engines selectable: Google | DeepL (Testing) | ICIBA | Reverso | LibreTranslate. Some instances are Tor-friendly, even onion. The project page seems to be codeberg.org/SimpleWeb/SimplyTranslate

Refusing to use Google is just common sense. LibreTranslate itself is decent (at least not Google), except a website hosting it may have some opaque JS or Google things (Font, Analytics, TagManagers, etc.)

Either way, translation can’t be super-private in general. For example, if you use it to write a private message or love letter in a foreign language… even including real names and physical addresses…

Also, metadata like “a Danish-speaker is reading this German text about X” can’t be hidden, and if the language pair is uncommon and/or if text to be translated is specialized (not generic), the engine provider may easily guess “this request and that request yesterday may be from the same user”, etc. if they want to. A sufficiently powerful “attacker” might de-anonymize you, helped by other info about you, already gathered. In practice, maybe not a big concern, if you’re just translating generic, non-sensitive text, not showing your real IP, and clearing cookies frequently.