... to reach the objective "renown". And how much money is enough money? and why can't I change objective later, as the freeplay characters can? Would make no difference, but storytellingwise it could suggest a change in my character, a possiblity i would find interesting.

Until now, I only reached the "wealth" end, and it was maybe 20.000 to 25000 broth or so to achieve this. But the exact demand is not fixed as sometimes, reputation or time can replace some coins. A good connection to at least one faction can spare you 6000 broth in one step, if I remember correctly.

For the renown objective, I can't recall the exact amount, but eventually you'll meet someone who will give you a more clearly-defined set of objectives to meet for this, where you need to visit 4 distinct places on opposite ends of the map. I think after you complete that, you'll get an indication of exactly how much renown you need.

By the time I completed that, I had WAY more renown than I needed to complete it, but as I had many unfinished quests still going (and others I hadn't discovered yet), I elected to keep going and come back later (which would end the game at that point).