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Joplin
Joplin - the secure note taking and to-do app with synchronisation capabilities for Windows, macOS, Linux, Android and iOS.
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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.
Website: https://notesnook.com/
For me, I'm comparing against Joplin. It does a great job of checking off your list of features no other app has, but is free / open source. Has features like e2e encryption, desktop / mobile apps, can use self hosted Nextcloud instance as a sync server, and has a variety of plugins like Mermaid (markdown based flowchart generation) that I use regularly.