Multiple Themes

Is the goal to have different pages have different layout and CSS?

I’m not sure what you’re comfort level is with php and the wordpress loop, but have you considered making different page templates to suit your needs? Here are some links that may be helpful:

https://www.wpbeginner.com/wp-themes/how-to-create-a-custom-page-in-wordpress/

https://webtide.wordpress.com/2010/10/05/how-to-make-custom-page-templates-in-wordpress/

Well I found different wordpress themes I want to use. I want them on one wordpress where I can use different theme for different section. Like Buddypress use a buddypress them, artists theme based around that, media, store, and so on.