I also want to throw another perspective into the room, namely the age when buying/building a property. According to Statista, the average property buyer in Bavaria was 39 years old (data from 2017). In the other federal states it is similar. In Saxony a bit less (38), in Berlin (41) and Hamburg (41) a bit more.
Most people here who have somewhat lower equity and income are under 30 in the forum - the OPs are even 2 years younger. That means they are 11 years (!) away from the average in Bavaria of 39 years.
In 11 years, if you don’t live in a completely overpriced rental and are accordingly frugal, you can save a considerable sum as equity. Both have a household equity of 4,300 euros - calculated over 11 years with corresponding salary increases, these 11 years make quite a difference. Assuming 2-3% salary increase p.a., the household equity would already be at 5,600 euros (2.5%). And that will still be conservative, especially in the late 20s / early to mid-30s you can get a bit more out of a job change.
Now ask yourself what is better in the current situation. Building directly without equity and a somewhat lower salary with the unconditional will to pay the rate and build your life around the rate or waiting 11 years, saving, building equity and then having a higher salary.
We ourselves have asked this question over and over again in parallel with the search for a plot of land - and ultimately came to the conclusion that we want to build immediately. Because we don’t want to spend those 11 years with a small child, etc. in the floor rental apartment, hoping for a garden in 11 years - but rather use those 11 years and give it to the child and ourselves. Who knows what will happen in 11 years? Live in the here and now! It will become clear what was better when I’m 40 in 10 years - maybe the forum will even still exist then ;)
The only important thing (after I’ve given the OP some food for thought) is that you, dear OP, are really not naive. We agreed on prices from the end of last year and some surprises are currently hitting us as well. If materials that you really! need become more expensive, then you simply have additional costs (I don’t mean the fence, honestly, who cares about landscaping in the year of construction, I find all of that here extremely exaggerated o_O) - all my friends who have built completed the landscaping over years, that’s how my parents did it and my grandparents. Everything else are rich people or those who simply want to show off.
Accordingly, please plan! And we did that too, at least!! 10% buffer on your calculation (that is after you have received offers for each trade or if you build with a general contractor, you have calculated additional costs). You wouldn’t believe everything that comes up that you don’t think of now (believe me).
If you take this into account, go for it - then you are prepared and can sleep well.