Bit of both really.

The more money I get, the more I want to give it away, so I'm going to guess the latter.

Often socio-economic structures also incentivize different behaviour for different amounts of wealth, so very often it's not just money and the person but all of society as well.

Money is power. Power corrupts.

A consequence free environment (boatloads of money) simply let's people be who they are. Unfortunately bad people come into money more often.

A lot of people have a limit where the effort of getting more money isn't worth it. People without that limit keep trying to acquire money and power.

Both, I'd say.

Money doesn't create corruption out of thin air - anyone who's corrupted by it already had to have the potential. But money does undoubtedly lead people who otherwise would have resisted their baser nature to indulge it instead.

And it very definitely provides the means for people who are already psychologically and/or morally inclined to corruption, and so is very attractive to them.

Yes.

Yes

Both. There is a study by Armin Falk and Nora Szech (2013) that experimentally shows that markets can erode moral behavior, as participants were more likely to not save a mouse's life for money in market settings. This generally extends to the erosion of morality for monetary gain in market systems. Additionally, psychological research indicates that wealthy, successful individuals often score higher on traits associated with the "dark triad" of personality, i.e. narcissism, Machiavellianism, and psychopathy, which supports the idea that selection plays a role as well.

That's kind of like, "What came first, the chicken or the egg?" It seems to me that when you give a regular person a bunch of money, like winning the lottery, they tend to go kind of nuts with it. So in that way, it seems that money is corrupting them. If you have some kind of ultra-rich person who loves money and power, then they're already corrupt because of power and money.

This tension is what causes the Bible to be suspicious of wealth

I think it's enough of a mix of both to where it doesn't really matter at the end which was the cause and which was the effect. I feel similarly about the vague concept of power, to which money is a manifestation of.

Getting money activates the reward process in the brain.

Everyone handles that differently based on their life experience and current situation.

If you're asking If money drives the moral compass that's highly individual.

Being questionable is a property of being human.

Neither. Just different beliefs, values, and choices.

“money is the root of all evil & poverty is the fruit of all goodness”

I say neither. Plenty of decent people find ways to make good money without selling themselves to the devil. Personal injury lawyers are a great example, they are real-life Robin Hoods.