The “problem” is not so easy to describe.
First: The generation of a list of sprites works now.
Why did I think that there is a problem? The answer is, that testing the app with thinkable live app (on iPhone SE and on iPad 2018) did not show any sprite. Now I found out, that it really last a longer time to generate the sprites with the create block and I gave up too early. For 20 sprites sometimes you have to wait up to minutes (for more than 20 it seems to be much more).
After several testing I found out that the delay is even much smaller when running the app after downloading it to the device.
By the way: It would be helpful for beginners to tell them what component means in the block “create…” and what they can do with it (e.g. object of type of the sprite-type).
Second: It still is not easy (or impossible to give sprites an initial direction of movement or determining the direction to change it(). I.e. the bounce statement seems only to work for the edges of the canvas. If sprites collide they do not bounce in my app. So I had to determine the direction of the movement of both to reflect them. But…see above.
If You have solutions for this please let me know.