Construction costs are currently skyrocketing

That's all true, but you can sacrifice your annual leave (almost) two or three times for DIY work.
You can then work hard for days or weeks. A lot can be done that way.
You work long days, the ratio of output to setup time gets better, you're in the flow, etc.

You (hopefully) don't go on vacation during or shortly after the house construction.

You might be "in the flow" when tiling after about 100m².
That means in the last room you look and say "Wow, that really looks professional now." Then you go to the first room and think "Oh God. I should actually redo everything now that I can do it properly."

Sure, DIY work is possible. But you have to be aware that months or years pass before everything is finished and you live on a construction site for that long.
The family has to cope with that first.

On the topic of tiling.... we recently did it ourselves in two basement rooms. Unfortunately, the substrate was not completely even and we also used very cheap tiles. I am actually quite satisfied with the result in the second room, but I consider tiling to be a DIY task that is really more for very, very skilled amateurs. It is not something you can quickly learn like drywall, painting, or laying laminate. Maybe in a utility room where it just goes straight ahead. But on walls, even the smallest difficulties quickly make it complicated, and you don’t have unlimited attempts. I am totally pro do-it-yourself, but I really exclude tiling from that.

Our energy consultant for KfW70EE renovation is charging 9,998€, which is 2€ below the maximum amount subsidized at 50%.

I have no values for individual measures.
As far as I know, KfW funding is only available for KfW85 anymore.

Our energy consultant for KfW70EE renovation is charging 9,998€, just 2€ below the maximum amount that is subsidized by 50%

That is why, for example, a Heidelberg wallbox is now available for 249 € instead of 849 €, when the subsidy was still available ;)

Yes, I understand. But he also has a lot of effort. Several on-site appointments, inventory, calculating the whole house, construction supervision and application submission and...

So you do get something for the money. If there were no funding, it would probably still be only €5,000 as a bill :cool:

Therefore, for example, a Heidelberg Wallbox is now available for €249 instead of €849, as it was when the subsidy was still available ;)

Today on mydealz, seen it, I also don't find subsidies appealing. No matter which ones, they became price drivers and the homeowner never benefited.