Unfortunately I have not seen anywhere you can download
QuickStart Installation Demo Packages for Joomla 4
Quickstart with Virtuemart (flex_3.9.9_quickstart_with_virtuemart_J4.zip)
Quickstart without Virtuemart (flex_3.9.9_quickstart_J4.zip)
I managed to use it with 4.3.4 and SP Page...