Zim has had a dollarized economy for a few years now. The local currency isn't used at all.
Indeed, they use USD, ZAR and gold, mainly.
And people will accept dollars in any country on the planet.
Dollars are not widely accepted in the EU. You'll need eubles (or pounds in the UK, crowns in Denmark, Sweden, Czechia, and so on). Gold and silver might pass muster, and maybe a few very touristy places handle USD at unfavourable exchange rates (to you!).