If one assumes the current trend [1] of the last 13 years, Germany should be at 84% in 2035 by simply not slowing down the transition. So honestly not overly ambitious
[1] https://energy-charts.info/charts/renewable_share/chart.htm?...
[1] https://energy-charts.info/charts/renewable_share/chart.htm?...
https://www.nature.com/articles/s41560-021-00863-0.epdf?shar...
[1] https://www.cleanenergywire.org/news/germany-build-no-new-of...
Some details here https://m.dw.com/en/german-cabinet-puts-brakes-on-clean-ener...
Given your projection, I don't wonder why