There are ways to pack up web-pages into extensions :) Like extensions that you can put a URL into and it will display the page, just mini.

Can I complain briefly on the extension thing. Browser extensions are BS walled gardens too. You have to submit your extension for code review for most changes iirc, and your repository has to have a particular structure, Fuck Google btw, never going to have a chrome extension. BTW You still have to do this process to get a signing certificate to distribute the extension yourself, otherwise no one can use your extension. They can temporarily load the zip file for debugging, but that has to be done every time the window is closed, not a solution.

For NVault I inject the UI into the web-page itself so you don't have to use the dinky little popup page that resets every time to click away. I like that it feels integrated into the app you're using. Not all apps work, so I have a toggle, that opens a new popup with the same window, but i don't like that flow.

example