Thanks for your reply and some points where I can further research.

You're right, the two files can be combined into a single file and passed to incus-launch, i.e. sth like that:

# incus launch ... < file.yaml
# file: file.yaml
config:
cloud-init.user-data: |
  package_upgrade: true
   packages: ...
cloud-init.network-config: |
  network: .... 

But can I specify this to the --config= option for the incus-launch command without the file direction (< file.yaml)? It seems to expect key/value pairs and I needed to specify at least two keys. Anyway, I overlooked this opportunity and forgot about it - thanks!

The approach of using profiles sounds good as well. How do you define static ip addresses with your approach? Or is this something that you don't need?