They are in fact doing an out and back on the Hauptdeich again. In 2024 and 2025 they did a larger loop which returned to Billwerder via Bergedorf and Allermöhe instead. However, there was significant pushback from Bergedorf residents to having the bike course and the street closures it brings along with it go through their neighbourhoods. It’s only the small loop after Howe which is different from the 2023 bike course. Earlier this year, there were some proposals of using the motorway 25 for the return leg of the bike course, but it’s pretty difficult to obtain a special use permission with road closures for federal motorways in Germany.