A lot of good advice this far.
To the OP, I wouldn't necessarily buy your second trailer first like mentioned above, largely in part to you being "totally new" to trucks and trailers. Unless you're already proficient at towing or are the type that isn't bothered by, whatever, learning the ropes with a smaller trailer is a good suggestion.
From the economic side, you live in FL where there's millions of trailers. I'd find a good deal on a used "1st" trailer so you can dump it for the bigger one without much out of pocket if you're planning on upgrading soon anyway.
Towing? Again, it's what you're comfortable with and the duty cycle you're looking for out of the truck.
I have a 2016 1/2 ton Chevy work truck that tows the equivalent of a larger travel trailer a fair amount. No issues with it, but I'm in the low mountains here where elevation isn't much of an issue and most of the grades are pretty mild. Same truck in COlorado would be sucking wind much more.
If buying a new truck with the primary purpose being towing a med or larger trailer, I'd strongly consider a 3-4 ton.