That being said some services that translate and respect privacy are out there. The one I know of off the top of my head is the one integrated into Vivaldi, Lingvanex. Source: about 1 year ago

We are partnered with lingvanex, all translation requests have IP/identifying information removed and such text is not retained after the request completes. Source: over 1 year ago

I loved when Vivaldi opted for translation services of Lingvanex "https://lingvanex.com/" and not of google but then you see they have DNS of google, chain of google enabled for login, phones back to google, dependant on google addon store, uses grid tabs and tab groups and the new share plate where only google apps show not the ones you use mostly to share things made by google for chrome, not for Vivaldi and... Source: over 1 year ago

Editsaurus is covered by the MIT License. https://editsaurus.tylerwalters.com/. Source: about 2 years ago

I use google docs and a mixture of editors. ProWritingAid is my favorite and has a free version (limited to 500 words at a time). I also use a few free editors on occasion: Editsaurus, Typely and Hemingway Editor. Editors are good for finding errors, but also just breaking your text down for you to help you find any weird patterns, overused words, etc. Source: almost 3 years ago

You can also use ProWritingAid free (which limits the word count of what you can put in and review). I prefer it to Grammarly, personally, and use it before and after sharing fics with my beta reader. They also have some blog posts that aren't bad. Hemingway Editor and Editsaurus have also been useful to me. Source: almost 3 years ago