I have understood it

1) I have understood it.

2) I understand it.

How do you feel when you hear 1) and 2) and do you think there is any difference in meaning between them?

3) I have gotten a lot of money VS. I have a lot of money. VS. I have got a lot of money.

I think if we want to tell how much we have now, I have a lot of money is natural and the others mean 'have received until now from someone' or I have gotten a lot of money can mean I have a lot of money?

And I know that 'have got' can mean both 'have' and 'have gotten' ,meaning have received. So we should distinguish in context, right?

Thank you so much as usual and have a good day.