If you sell, you get $500k added to your stash that would kick off $20,000/yr income per the 4% rule.
If you buy, you pay $500k to add $70k/yr in gross income, but then you'd have to subtract debt service, property taxes, insurance, vacancy, CapEx (which could be significant early on), etc. So you'd be taking in $70k in rent, but probably spending around half of that? More?
Is the hassle of owning worth the difference between those two? $20k/yr to do nothing, or maybe $30-35k/yr to be a landlord in NY?
The insurance situations in coastal places like Florida would be giving me pause too. One day you're fine, and the next day you can't get covered without your rates doubling. It might work out, but there's some risk there for sure.