Why is the created theme not applied in opencart 3?

Question

opencart

created a theme copied default and in the settings in the admin panel in modules -> themes -> specified the directory of the created theme, but the default theme is still shown

Answer 1

Just copying the theme to another directory is not enough.
You need to go through all the theme files and change all paths containing "default", class names containing "Default" to your theme name. Similarly with settings keys and language files.
If all this is done, then you need to go to Extensions -> Templates and click Install opposite your theme .
Then enter the theme settings and set the status to Enabled .
After that, the theme will be available for selection.