In this case I think the renewables target is better. CO2 reduction is the goal, but having it as a single target can lead to lock-ins. Especially when the target is only low CO2 and not zero.
E.g. you could reach an 80% goal, while still expanding the use of fossil gas to replace coal and lignite. But we need a system that goes to 100% renewables by 2035. And first ramping up gas to then switch to renewables after is what got Germany in this mess.
Of cause that is a BS reason. But they should have stopped using fax machines 20 years ago. How can any reason they give why they have to stop now be any other than BS.