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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.
Wikipedia has a page on single-user personal wikis that are great for organizing your notes[0].
If you're looking for something simple and unixy, Zim is a pretty good choice[1]. It's an offline GTK-based GUI application for creating personal wikis that saves all the wiki pages as Markdown files and can export your wiki as HTML using various templates. Zim has been available in many linux package repos for over a decade and is GPL-2.0 licensed.
[0] https://en.wikipedia.org/wiki/Personal_wiki?useskin=vector#S...
[1] https://zim-wiki.org/