Help with theme and some customization job

Hi, i wanted to ask , what additional modules i will need to make your pluging work with the following wp theme: https://www.shindiristudio.com/sierrawp/landing/#select-demo

i will need to make to following functionality: one page with only some of the tabs active and viewed by every visitor, then if customer wants to pay for subscription, he will get access to the following pages BLOG page, PAGES – blog archice, blog posts, and SEARCH bar of site and of blog content. So my idea is BLOG page, PAGES – blog archice, blog posts, and SEARCH bar of site and of blog content to be hidded and only registered memebrs can access them. Do you think this can be done using this theme and also will your pluging will manage the registration of customers/passwords that will be needed to access the paid features which will be BLOG page, PAGES – blog archice, blog posts, and SEARCH bar of site and of blog content, which is all visible now in the header menu. also if i can’t do this by myself how much it will cost to do this job for me?