Hi Harald,
Greetings from Syncfusion.
Currently, we don’t have WYSIWYG designer for Blazor but we have already logged a feature request on this and it can be tracked through our feedback portal below.
Please cast your vote to make it count. We will prioritize the features every release based on demands.
If you have any more specification/suggestions to the feature request you can add it as a comment in the portal.
Regards,
Sridurgha U