Hello Gustavo,

Yes, It is possible to restrict the joomla content on your site you can use Content Acl app to restrict user to view content on your site the user need to have a subscription to view the selected content on your site,

You can refer to this document for more information:https://stackideas.com/docs/payplans/administrators/apps/content-acl

And can I also restrict Easyblog articles and make users pay for them?

In Easyblog you can not put restrictions on articles directly but you can restrict the categories for the articles.

You can refer to this document for more information:https://stackideas.com/docs/payplans/administrators/apps/easyblog-Category-Access-Restriction

Let me know if you have any other query.