Newly built photovoltaic semi-detached house - offer comparison

Quite simple: fill the roof completely, everything that is possible. And skip the storage for that (unless it is subsidized or a subsidy requirement for a new standard).

I believe storage is often "standard" today because that's just how it's done nowadays.
At least that's what the solar installer claimed ;)

I agree with my predecessors. First and foremost, put as much photovoltaic on the roof as possible. There is no such thing as too much. What you don’t consume yourself displaces coal power from the grid and pays off the system.
If the north roof is really 45° steep, you probably have to leave it out, unfortunately. If you still can, build 20°, enjoy the higher knee wall and fully equip the north side as well.

And if you still have money left to burn at the very end (that’s all a storage system does right now), then you can gladly buy a storage system for the good feeling.

If the north roof is really 45° steep, you probably have to leave it out unfortunately. If you still can, build 20°, enjoy the higher knee wall, and fully build the north side as well.

Now a very quick question, I’m almost embarrassed, but it keeps confusing me over and over... If I look at a compass, one half of my roof is on the west side and the other half on the east side. So the gables are basically facing north and south (exactly even). Do I then have a N/S orientation of the house or a W/E orientation of the house? Or do you differentiate between house orientation and roof orientation?

... Because the way the house stands now, as far as I know, it’s actually perfect, because in the morning the sun rises on the right side (east) and can shine in, then at noon it is in ridge direction, and at noon it shines on the left side (west).

This is so cool, today I visited 2 photovoltaic system companies. One wants to install 18kW without storage, the other 10kW with storage. Both companies argue in such a way that the consumer (so me) finds both plausible and cannot avoid fully familiarizing themselves with the topic and then deciding their (so my) own path. There are so many variables from power to feed-in to reimbursement and winter and summer etc., dude but today it couldn’t be any easier. Slowly I’m starting to believe those people in my environment who say, screw the subsidy (which wasn’t my motivation anyway) just get a gas boiler and that’s it. I simply can’t and don’t want to be as knowledgeable in every area of my house as the person selling it to me. ... can you send me a PM where I might be better off with my topic?

No, you don't have to read up - the 18 kWp colleague is right :) The important thing is first of all to have as much photovoltaic capacity as possible. In winter, you will be glad about every kWp. And in summer, the surpluses don't bother you since they pay for the system (even more so with a west/east roof).

A storage system does increase self-sufficiency and self-consumption - but currently still unprofitable (and ecologically questionable... these things are not exactly compostable). Buying a storage system today only makes sense if it is directly subsidized or a funding prerequisite for, for example, Kfw 40+. Otherwise, a storage system can simply be retrofitted, meaning you can also tackle the storage topic when these things become cheaper in a few years.