I can assure you that the comfortably rich are not getting richer by loaning money to the average person to buy houses and cars with 2.5% interest rates, while inflation is arguably significantly higher than that number.
The rich get richer in this scenario because low interest rates increase the buying power for everyone, which means they can buy more expensive houses or pay less for the mortgage on the house they already own, which in turn means they can buy more things from Amazon, which means Amazon does more business, which means the stock price goes up, and so on.
The populist narrative likes to simplify complex economic topics into rich versus poor narratives as if this was a zero-sum game, but it’s not. I’m not sure how your final points about inequality relate to increasing total global debt, but it’s obvious that this isn’t as simple as funneling money from the poor to the rich.