I can not get a consistent style

I can not get a consistent style when changing the motive/object and leave all other params I've set unchanged. It's getting even worse when you have a new "session" by closing the browser or tab.

So I tried to do the generation in a Board because I can set the seed in the prompt settings.
But this does also not work.

I have this issue with using the predefined styles/effects/... or a complete text only prompt.

Anybody has the same experience.?
Seems I have to use a different image generator when I need consistency across multiple images