There should be some init commands like:
mkdir app
cd app
snapcraft --init Python --name App --LTS
snapcraft --init Flutter --name App --LTS
snapcraft --init Flutter --name App --LTS --plugs=desktop,camera,usb,preserve-security
and maybe some selection like popular web frameworks init to select backend and options but it could be another project. But then maybe:
snapcraft --use=joe/doe.git
and selecting options then via text based graphics
and maybe also some scripting options to use some yaml to get preselected some option to make it more automation friendly and not need to remember a lot of options for simply make snap with a lot of already made solutions when Python, Rust or Flutter already have some default paths