8
The best practice is still to use Drupal's behaviors system even when not relying on jQuery. See Drupal 8 Drupal.behaviors without jquery for reference.
That said, I think you're on the right path. I find jQuery just slows down the page load when vanilla JS will usually do the trick. That's just my opinion and there's a lot of debate out there.
2
To use state for checkboxes element, you should target the specific element by JQuery selector, all elements they have the name="field_select_shipping" with value attribute different so try to target the input with both attributes try with the following to show adresse_home only if home and colissimo checkbox checked:
$form['input']['adresse_home'] = [
...
Only top voted, non community-wiki answers of a minimum length are eligible
