Use keyboard navigation to use the select. You can use ENTER ↵ to activate, arrow keys: ↑ → ↓ ← should all work to navigate

You should also be able to drag the options and by stopping and clicking out of it, the centered option should be selected. Arrow keys are also provided for people that don't want (or are not able) to use drag or keyboard

Notes on accessibility: A direct click of an option doesn't work, still there are alternatives created. The "centered is selected idea" is part of the experience in this UI. In this context it might work, but remember, context is everything.