Hi Stefanija,
I checked your site and your ideas/requirements, I think you need a WooCommerce
and some plugins like WP Courses (free learning management system), WooCommerce
Memberships, WP Elementor or DIVI template/DIVI builder for rich contents edit.
I'm an experienced full-stack web developer specializing in Linux, PHP, MYSQL,
WordPress, Laravel, CAKEPHP, MAGENTO, CodeIgniter PHP, Prestashop, Shopify,
AWS EC2/EC3/T2/T3, cloudflare, bluehost, VPS.