Construction costs are currently skyrocketing

I once read that by 2030 even 70 cents/kWh would be possible! But it could just as well swing the other way – though not as drastically.

New contracts are already at that level currently.

New contracts are already in place.

We will see these prices drop again...

But doesn’t it make more sense to put the 24 modules only on the south? Instead of splitting them up like that? In what numbers and which orientation?

I would rather have argued to get rid of the storage and instead fully allocate the money to east, south, and west. That way you still have quite a bit to manage in winter. But such nonsense with a few panels here and a few there......

I have 30 modules on a good south-facing gable roof.

Somehow your post confuses me a bit :-D
In the first paragraph, you question the constellation (east/south/west), and in the next you suggest exactly that. ;-)
Or did I misunderstand you?

If I had more south-facing area available on the hip roof, it would of course have been implemented in the plan long ago. But unfortunately I only have space for 6 modules on the south side. I also hadn’t planned any storage, and none was included in the offer for the 20k either.

But I finally have a second offer. Based on LG inverters and Cortex P3 solar modules. I haven’t dealt with the details yet. If I remove the storage, the mounting system, and the registration with the utility from the offer, I come to 16.3k, which I find "reasonable."

Presumably it is even the case (looked it up today on purpose) that existing systems for which the input tax has already been claimed and reimbursed can now be switched to "hobby activity" without consequences of partial repayment (however, this apparently only applies up to a total of 30KWp of all systems owned by one owner)

Hobby activity and sales tax have nothing to do with each other. The exemption from the sales tax obligation is in my opinion merely a simplification. Until now, the input tax from the purchase was deductible, but the income and own consumption had to be subject to sales tax. After the correction period expired, one switched to the small business regulation and then that was it with VAT. Until then, however, declarations had to be prepared, income/expenditure accounting, etc. THAT is now no longer necessary.

The new regulation is indeed simpler, but is likely to be financially disadvantageous because then depreciation on the asset would also be omitted?

You see. Exactly for this reason (because it is so complicated) Germany is preventing the energy transition