Within bootstrap theme, print radio item with label and input as siblings instead of parent -> child
At first I was going to say hook_form_alter, but when I started digging into the Bootstrap theme I found they've created their own plugin system. I would checkout this page, you might be able to get to the render array by creating a Bootstrap theme plugin: https://drupal-bootstrap.org/api/bootstrap/docs%21plugins%21Form.md/group/plugins_form/8