500 Error - Laravel Project Deployment on Shared Hosting

I have difficulty deploying my laravel project on 1and1 managed hosting. And specifically, adjusting the .htaccess so that there is no 500 error when trying to access https://www.muza-store.de

My project structure:

/muza-store
    /public
        .htaccess
        index.php
        php-errors.log
        php.ini
        ...
    /resources
    /routes
    /storage
    .env
    ...

I just changed the project root to the /muza-store -directory. The public-directory as the root didn't work because the other directories and files above the root-directory couldn't be accessed.

This is the content of the .htaccess-file:

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews
    </IfModule>

    RewriteEngine On

    # Handle Authorization Header
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

    # Redirect Trailing Slashes If Not A Folder...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} (.+)/$
    RewriteRule ^ %1 [L,R=301]

    # Handle Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]
</IfModule>

Unfortunately, everything I tried didn't work at all.

I would greatly appreciate ideas, tipps and resources to learn more about .htaccess -files.

Thanks a lot!