You also forgot the opportunity cost of your down payment. If it’s 20% of 325K, that’s 65K which would get you 3250/yr at 5%. Of course you’ll pay tax on that, let’s say 27% leaving you 2372/yr income on your money, just under $200/mo for keeping your money safe in a money market account. So your $1800/mo rent (probably realistic rent for a $325K condo) is really only $1600/mo.

There is no way that a $325K condo rents for $2100/mo. Maybe people are TRYING to rent them for that, but it would be rare for them to get that. I rent a nice place that would sell for at least $750K for less than $2500/mo.