Define the pages first
List the templates your site needs: homepage, category archive, article, review, and search results. Then look for a theme that supports those patterns with the editor you intend to use. A beautiful demo may rely on extra plugins, paid features, or content that will not match your own.
Test real content
Use a long title, a short title, a table, and a mobile menu in your trial. Check line lengths and how the sidebar behaves on small screens. Try changing the font and accent colour globally. A theme should make regular publishing easier rather than require custom fixes for every post.
Compare the total setup
Record the theme cost, required add-ons, renewal terms, and maintenance work. Kadence and GeneratePress are examples worth evaluating; neither is automatically best for every project. Start with the features you need and add paid tools only when a specific limitation justifies the expense.
Keep customizations maintainable
Use the supported editor and theme controls first. Put code changes in the appropriate child theme or custom plugin rather than editing vendor files. Keep a record of the changes. Test updates on staging and check that article layouts still work before updating the live site.
Your next step
Judge a theme using your own pages and publishing workflow, not only the demo.