GOOGLETRANSLATE() in spreadsheet is shit, it does not preserve html tags and translated text quality is very poor

So use this page which translates through actual google API

You should use this from Tor Browser, with CORS Everywhere extension installed and cookieBehavior fields set to 0/false in about:config

(if you don't need a proxy, you can also use this tool from chrome by running it with chrome.exe --disable-web-security --user-data="C:\tmp"), see disabling CORS