I would say that beyond the green corridors, the main difference is how global it feels now. Lots of international cuisine, international DJs playing here, foreigners around, real estate ads in English, etc.

I assume the COL has only increased, am I wrong?

Yes, even compared to 2 years ago...

But the prices of "nationally-distributed" "things" (e.g. laundry detergent right?) pretty much adheres to the national trend...

...however rent in Medellín has gone up in these past 2 years too, like in some places it has gone up to double, gotta account for inflation (in USD terms you know) too but still...