I use VScodium with some plugins. But writing in any editor and running the typst executable with the “watch” argument is also an option. That way as soon as you overwrite the source file a new PDF is generated. In that case I use Okular which auto refreshes when the open document changes.

There are other note apps that can sync with Nextcloud. I settled on Quillpad because of its checklist functionality, though admittedly it’s not perfect.