I use that one on iOS. In Firefox I use the native functionality (the cookiebanners.service.mode flag). See https://community.mozilla.org/en/campaigns/firefox-cookie-banner-handling/. I also set cookiebanners.ui.desktop.enabled to true to make this setting appear in the settings menu.

Using English is the only way that all my colleagues are able to read it, but if it’s just meant for you, or only for Spanish speaking people, I’d say why not.

Telegram’s “privacy” is fully based on people trusting them not to share their data - to which Telegram has full access - with anyone. Well, apart from the optional E2EE “secret chat” option with non-standard encryption methods that can only be used for one on one conversations. If it were an actual privacy app, like Signal, they could’ve cooperated with authorities without giving away chat contents and nobody would’ve been arrested. I’m a Telegram user myself and I from a usability standpoint I really like it, but let’s be realistic here: for data safety I would pick another option.