Ask HN: How to build a web app for a non-tech savvy client who wants to modify?

My client needs a site that can integrate eCommerce (Shopify), membership accounts/privileges, and a YouTube-embed carousel/slider. The client desires the ability to add/delete/modify sections after my development work on the project is completed (without any programming). Client needs, example: “I want to be able to add one, two, or three columns containing pictures, videos, text, on pages/regions in the future.”

I already tried using WordPress Business Plan and it didn’t work out as there is not enough flexibility with plug-ins to achieve main goals. Self-hosted WordPress seems to be the next alternative; yet, this would almost definitely require programming for client to make changes in the future.

Are there any free/open source recommendations? Or, paid recommendations? …this could be an existing platform or app, or a concept for development altogether (holistic; combination of technologies). Thanks HN