So Google could solve this problem by raising the price of its OS, increasing profits and decreasing market share, and leaving a billion with no access to smartphones at all.

Or, by doing something that is not illegal in the EU: not forcing manufacturers to bundle Google Search if they want to include the Play Store.

Android is free to license. Google makes money from the Android users who then use Search, Gmail, Maps etc. since they are bundled with the phone.

Well, there's nothing all that special about the output of a political commission. And the fact that 1 in 5 devices don't run Android would seem to contradict the monopoly accusation.

Antitrust does not require a monopoly, it just requires enough of a market dominance that hurting the market is feasible for you, and then exploiting this position to actually hurt the market.

Basically, all you have to do, is hurt the market in noticeable ways. The sole goal of antitrust laws is keeping the market healthy. They're not fair and have almost no rules attached to them.