Hi Jörg
I looked at the flowchart and, although long, it seems simple enough, in that the question on the third slide doesn't depend on what was chosen in the second slide, etc.
So I think you can do this with CRED using conditional display as described in the link I shared above. The test in each condition would be whether a selection had been made in the previous step, so that once it had the next step would be exposed.
How nice it appears visually will depend very much on your CSS skills, as CRED forms have only rudimentary styling by default.
An alternative method for multi-step forms with CRED—given that this is a simple form, would work like this:
The first slide is a CRED form to publish a post, which contains just the initial field the user must select.
When they make the selection the form is submitted and it creates a post with that field stored, and then it redirects to a second form which is a post edit form that edits the original post but which only includes the fields you require for the second slide.
When the selection is made on that slide, the form submits and redirects to a third form which is a post edit form that edits the post and includes only the fields required for the third slide, and so on.
You chain together an initial create post form and then a series of post edit forms.
There are a couple of points to bear in mind with this approach in your specific case.
The first slide will contain only a field (probably a radio field), but when creating a post the form must include the post title, so you will need to automatically generate a title and hide the title field with CSS.
Also, each slide won't have a submit button for the form, so you will need to programmatically submit the form with JavaScript once the field selection has been made.
Either approach would work, you can choose whichever you are more comfortable with.