For other page, I'll use full-blown SolidJS (with JSX and everything) for like a popup. Example: https://pasteboard.co/hY35xM7VbATG.png
Now, how I specifically embed SolidJS, its pretty simple, I have my entrypoint files for specific pages: assets/admin-edit-book.tsx assets/admin-edit-song.tsx assets/single-worship.tsx assets/worship-edit.tsx
Then I have a 30-line build script that invokes esbuild along with esbuild-plugin-solid (to compile JSX to plain-old html, no fancy virtual dom) to compile the scripts into javascript.
I can share the build script if you'd like. It helps that SolidJS is so self-contained that it makes such a setup trivial.
https://gist.github.com/BookOfCooks/42181c4214442144c3e4d7e5...
For passing data into it I've used Inertia.js [0] and also my own data-in-page setup that's parsed and loaded into the Vue app. The app then writes the changes back out, usually into a hidden form input. The form on the page is then submitted as usual to the server, along with any other data that I need.
It's a great way for adding more complicated behaviour to an existing app.