Construction costs are currently skyrocketing

It ultimately depends on how high your own net salary is and how quickly you can perform work. Usually, it takes twice as long and if you earn around 35 euros net, that would be 70 euros net for the craftsman. You can definitely get quite a bit done for that...

This back-of-the-envelope calculation only works if you do overtime to earn the money additionally or take time off to perform the work.
If you do it in your free time, you can count it as a hobby and actually save the money.

Creating a slope is simple. However, creating the correct slope at the correct height is more difficult. Especially hitting the right height as a layperson is really hard (it settles during compaction depending on the layer thickness), we had to redo it several times on the slab foundation of the garden house.

And first of all, you have to have the possibility to earn more money with overtime.

Yes. But then you don't complain about high prices.
And that's the point here. That people complain about craftsmen charging high prices.

Apart from that, it's not rocket science to create a slope. And as for professionals...
I can show you 3 or 4 terraces in my immediate vicinity that were made by professionals and have no slope at all ;)

Not everyone is complaining about the high prices. A price was posted here and then DIY people like you come along and say that you could do it yourself for x-thousand euros less and that it is way too expensive. Those who complain about the overpriced craftsmen are the ones who do it themselves anyway...

Craftsmen have often looked at me quite puzzled when I said "I am the paver..." or "Yes, I’m doing the interior finishing including the doors myself..." or "Nope, we’re taking the oven from our old kitchen with us..." or (my personal favorite from yesterday) "for 500 EUR I would have had it (the furniture for the living room) assembled..."

That has happened to us often as well. We currently have a renovation going on in the ground floor; that is the last floor, then we're done. We have done the other floors ourselves. Now we have commissioned craftsmen and there are always such questions. The energy consultant asked me who planned and coordinated everything. Yes, me. The builder^^. I don’t need an external person for that. It’s just a floor renovation; a skilled layperson can handle that. And for the new kitchen, we also kept the old oven, the old ceramic hob, and the old sink. Because these items are still perfectly fine. We can do drywall, plastering, a lot with wood, of course painting and wallpapering, we have even laid tiles in the basement. We can do basic electrical work, install windows and (house) doors, and who knows what else. I will also sand and varnish the stairs myself. I’m not willing to pay hundreds of euros for something like that. What we can do ourselves and if it is at all feasible, then we do it too. You just have to sacrifice time. We will also be taking down the ceiling in the hallway in the next few days.

Some jobs are quite expensive BUT very easy to do yourself. We gutted the bathroom of about 7sqm. Costs: €338 for the mixed debris container, €30 for coffee, beer and lunch for the helpers, 4 men and some tools from acquaintances.

Price from the plumbing company was over Ü2k.