[ahartmetz]

Regarding your first point, instantiating a lot of QML items is usually what makes startup slow. You can use Loaders to load things on demand (and timer triggered Loaders to load stuff you will probably need but shouldn't delay startup). Make the Loaders asynchronous and timer triggered (async but immediately triggered still slows down startup) and switch them to synchronous when their contents are needed immediately.

I have a component for it, it's 10-15 lines or so.