What I will say: it does not look like 'Vice City with a ring road'. Rockstar named a whole state - city, keys, swamp, factory town, faded coast, national park. Size is going to feel like travel time, not a loading-screen statistic.
Why I ignore the viral measurements
Trailer cameras lie. Haze compresses skylines. People count pixels, then argue in the comments. Fun hobby. Terrible encyclopedia.
If Rockstar wanted a boast number, they would have printed it. They have not. Until someone drives the border in a review build, 'bigger than V' is a vibe, not a fact.
The shape is the real spoiler
Water chops the city into islands and funnels you onto bridges. The Keys look like long, dumb drives over ocean. Grassrivers looks slow on purpose. Mount Kalaga is the 'wait, Florida has hills now' card.
That variety will matter more than raw acres. A swamp that takes twenty minutes to cross can feel larger than a huge empty desert. GTA has always cheated scale with density. I hope they cheat it well.
Fan maps are homework, not canon
I like a good reconstruction. I like it more when the author labels 'confirmed', 'probably' and 'I made this road up'. The bad ones flatten all of that into one pretty image and then it lives forever on Pinterest.
Use them as a conversation. Do not plan your 12-hour stream route from them yet.