Mac mini M4 compatibility with 220-240V city power grid

Yes.

Electrical and Operating Requirements

• Line voltage: 100–240V AC
• Frequency: 50Hz to 60Hz, single phase

Mac mini (2024) - Tech Specs - Apple Support

Well, all power grids are in the kilovolts, mostly AC. They’re converted to residential 110/220 AC by a local transformer, see https://engineering.stackexchange.com/questions/60817/how-is-the-city-power-grid-routed-and-connected-to-individual-locations-such-as.

So technically at least, the correct answer to your question is “What? What?”. But practically @John Galt’s reply is the response you want to file. On the money +1 (but feel free to like my reply too 😁).