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SurveyJS
Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.
Technologies like MDX make it easy to build dynamic frontends. They are sort of analogous to WordPress shortcodes but probably do even more.
If you're a programmer, the "JAM stack" is far easier to manage than WordPress. Some good examples are Gatsby, Next, Nuxt, Hugo, Eleventy, and Sculpin. (I haven't used the latter two, but the first three require some JavaScript knowledge. Hugo might be the simplest. My preference is Gatsby.)
You can gradually add dynamic features by using cloud functions. Fly, Gatsby Cloud, Firebase Cloud Functions, and AWS Lambda, are free or inexpensive ways to add backend features.