You are quite right to be puzzled, because there is no general answer, but to say that "it all depends on the position" does not help you very much.
Let me just comment on some of your remarks.
If the WB retreats to b3, and Black captures, there can be drawbacks to each recapture, but there can be benefits also. axb3 opens the a-file. Black might have to defend their a-pawn with a6, and then b4 - b5 might start a Q-side initiative. Nxb3 might be start of a dark-square bind if c5 is weak. Qxb3 might form part of an attack on b7 or f7.
Playing Bc2 looks a bit passive, but would be correct if Black has many pieces left but not enough space for them. Perhaps, since you have already played c3, you can follow with d4, and the Be6 might get into trouble.
Playing Bxe6 certainly has the drawbacks that you mention, but only if Black has time to take advantage of them. If White is able to play a quick d4, then they threaten dxe5. After ..dxe5, Black would have isolated doubled Pawns. If Black plays ..exd4 to avoid this, then after Nxd4 or Qxd4 White may have a strongly centralised piece.
There is potential here for a very long answer, but I think I can offer some short advice. Make yourself aware of all the possible pros and cons. Play through a lot of master games, perhaps including some old ones, and observe the themes that come up frequently. Pay special attention to games in which something that you thought was a rule gets successfully broken.
In your own games, take the route that seems best suited to the position,
but also the one that best suits your own style. Do you value sound pawn structures or open lines?
Remember that decisions can be postponed. It is broadly true that strong players are happy to leave unresolved tensions on the board. They say to themselves "Perhaps I will have to keep on spending time on this, but then, so do they!"
Take heart that the question you have raised is genuinely difficult, and the fact that it poses problems for both sides is why the Italian game has returned as a serious opening.
