A residence permit is not a prison sentence that must served to the end.
It is permit that allows you to remain in a country for a specific period.
In Germany, a residence permit will automatically expire after 6 months outside the country or is to be assumed to have left permanently (left your job, deregistered and have left taking your belongings with ...
Plans change. You expect to get an offer.
Right now your plan is to take a 10-month job, and any ideas of leaving early are "if and when." So you have no other choice than applying for a 10-month visa.
Ending that contract with all necessary notice periods and leaving earlier would be a change in plans, and you can make that change. Later.
We went for 21 days, we spent 4 nights in Hungary, 5 in Paris, 6 in Spain and a couple here and there in Belgium and Germany.
You should have applied for the visa at the Spanish consulate, since the primary portion of you visit was in Spain (6 days).
Had you also stayed in Hungary (where you applid for the visa) for 6 days, then the country you entered ...
You are considering booking separate flights for your trip. As David indicates, this means that if you are delayed, you are most likely on the hook to book and pay for a new ticket to Warsaw (and usually the return flight from Warsaw to Paris as well).
Tickets booked at the last minute can be quite a lot more expensive than tickets booked in advance. And if ...
The SFO > CDG flight is international, departing the US and arriving in France (a member of the Schengen area).
While the flight from CDG > WAW is international (between countries), it is from one Schengen state (France) to another Schengen state (Poland). Inter-Schengen flights are without systematic Immigration checks.
If you fly on separate tickets, ...