It might be helpful if you said where in South Florida? Key West prices won’t be the same as Homestead or Naples.

Not enough info. One can effectively double, triple or quadruple the cost of building a "custom" house anywhere by selection of finishes, cabinetry, appliances, and even design.

In 2021 we built custom with a great GC in SW FL, and if you really add up everything, we probably ended up around $400/sq.ft., which does not include the land/lot.

Mid-high end finishes. Marvin windows and Euro-wall sliders. Includes pool/spa and pavers.

Why owner/builder? Do you have experience in the building trades?

You will lose money in the time it will take to get the good subs to show up and then to return to finish your one off job.

You can spend $500 a square foot, or you can spend 1K a square foot. And you can get into big big issues with your bank loan getting called, because you can't get subs to show up and take you seriously. GC's have all the good subs sewed up.

" GC's have all the good subs sewed up." True, and I've got the receipts.

The villas next to my condo got a foot and a half of water from Hurricane Milton. My flooded neighbors called their remodeling GC afterwards and asked him what to do. He told them "Nothing. I've got this." And he did. All the best subs in good order. You're never getting his subs. Hurricanes come and go, but top GCs with steady work earn loyalty.

Another wealthy neighbor flew his subs in from Chicago.