I can hardly imagine that it isn't worth renovating with KfW, provided you renovate comprehensively
Yes, yes, for individual measures there is now 20%, but you can get the same amount as a tax reduction without KfW. And even better, through the tax you can get 20% of a max. €200,000, so €40,000. Without the annoying energy consultant! KfW can't do that.
Of course, you can do the first €50,000 through KfW, the rest through the tax.
Everything can be read in the law "Tax reduction for energetic measures in buildings used for own residential purposes"
I will start a separate thread about this at some point.