I have successfully completed the conversion of the homepage. I've spent a lot of time and effort adapting the Greensteel template to my liking due to lack of experience.
I looked at the „original“ Dokuwiki template, whose functionality is convincing, and took it as a basis with the help of my experiences. I'm amazed at how few changes are required and how the Wiki is preserved in its current form.
Roughly I have
I plan to publish the newly created template. This requires a version that does not contain any personal data (like the QR code).