If you want to redirect all subdomains for a domain, this is done with a wildcard record: *
If you have already specified your own subdomains under a domain, there is no wildcard solution for this level. In this case a separate wildcard record is required for the created subdomain.
So far you have created the following entries:
If you use admin.blog.yourdomain.de you will notice that the wildcard for * .blog.yourdomain.de is not taken into account, but only for all direct subdomains that were not created separately.
In this case, all not explicitly created subdomains below your domain are forwarded as wildcards including sub-subdomains.
Below the blog subdomain, however, the forwarding for your subdomains is not carried out using wildcards, since the blog subdomain exists as a zone and does not have its own wildcard entry.
If you need the wildcard for the zone * .blog.yourdomain.de, this must be created separately.