If you go with a builder, here's how the checklist maps onto FolioPress, so you can compare it with whatever else you're looking at. - Languages are tabs on the page. When you create the site you list the languages you write in; the first one is your primary language. Each page and post has a tab per language, and you can add a language later and translate at your own pace. The quick start shows the real screens. - Translations are drafts. Press Translate and the AI drafts the whole page from your primary language, including the title and search description, inside that language's tab. Nothing publishes until you've read it and saved it, and you can write any version yourself instead. More on that on the AI translation page. The AI has a monthly allowance, shown on your dashboard. - The search setup is automatic. Every language gets its own translated address, hreflang tags on the page and in the sitemap, self-referencing canonical tags, and translated titles and descriptions. The details are on the multilingual SEO page. - Missing translations stay missing. A page with no Portuguese version simply doesn't appear in Portuguese; visitors get your primary language instead of a broken link. - A domain per language, if you want one. One domain for the whole site, or a different domain for each language. - Every feature in every plan. Bilingual is €12 a month or €120 a year for one site in two languages; Multilingual is €19 a month or €190 a year for every language you need; Studio is €49 a month or €490 a year for five sites. No limit on pages or posts on any plan, and the first 30 days are free. See pricing.
What it isn't: a plugin for the site you already have. If you need to keep your current platform, options 1 and 2 are the honest answer, and the checklist above is how to get them right.