What is in Paraguay that could attract a retiree from the 1st world? Maybe if you're an exiled dictator.Paraguay is on my list of options that I'm researching.
It has drawbacks versus Argentina: It's land locked, less developed and hot, but the cost should be less and the visa process is very straight forward. Like you just deposit a small amount of money in a bank and you get a long term visa. Also, no taxes on income from outside of Paraguay as I recall. So, that's a plus as well.
I've never actually been there though. I'm sure it's not as nice, but maybe nice enough (?)
As for COL, yes probably very low