Which is a duo?

Huawei P 30 lite or Xiaomi Mi Note 10 lite?

or do you have a better suggestion?

IT HAS TO BE DUOS!

Do you mean dual sim?

Yes

What is "DUOS"? What does that mean?

Both have a dual SIM slot. Alternatively there's the http://geizhals.at/2283542.

Top hardware at a low price. The P30 Lite can't be compared very much with the Mi 10 Lite, as they are quite different in their price range.