In 2021, he competed at the European Championships in Kyiv, Ukraine, reaching the semi finals in the mixed doubles with Herttrich and the finals in the men's doubles with Seidel. Unfortunately, he was tested positive for Covid-19, and the organizers decided to cancel the finals. Nevertheless, Lamsfuß then received a silver and a bronze medals for his achievements in the tournament. In July, he competed at the 2020 Summer Olympics in the men's and mixed doubles but was eliminated in the group stage in both events.