Generally, the repo seems to work fine. But I would add the line metadata_expire=6h because this repo seems to be also intended to provide potential (security) updates for the package you want to install. Especially security updates should be installed asap. Formally, type=rpm might be added as well to make everything explicit but this is unlikely to cause an issue (dnf should enforce this indirectly anyway).
The reason for the error is not the repo but the package: the package you want to install needs another package: libgtkglext-x11-1_0-0 → this is not contained in any repo.
However, you maybe try a refresh (the data you provided doesn’t show the state of the database) before we elaborate more sophisticated troubleshooting: dnf install anydesk --refresh → please provide the whole output of this command, just to see what repos are currently involved.
Be aware that this repository is maintained by anydesk (not the Fedora community!) and therefore, this repository has not undergone the testing and quality assurance of the Fedora community!