Set default image alignment

Thanks for using the Insert module. You could try to just overwrite insert-button-widget.html.twig, putting a copy of the file into your backend theme's folder and moving the checked attribute to your desired default radio input. That could already do the trick.

If there was a module or field setting for it, it would not work much differently, just that the setting would then be injected into the template file instead of having to overwrite template. If overwriting the template works, I would suggest using that method for now rather than adding a setting as this is so far the first time the feature is requested.

Having a bit of time to try this out, it does not work just out of the box unfortunately. But I have attached a patch set that would achieve being able to use the way I described in the previous message. Using the patch, I can simply copy insert-button-widget.html.twig into my backend theme's folder and move the checked attribute to another radio button which would then be the default alignment.
If there is no custom backend theme yet, creating a sub theme is pretty straight forward: https://www.drupal.org/docs/theming-drupal/creating-sub-themes →

Automatically closed - issue fixed for 2 weeks with no activity.