At the right altitude where you can "float" on the ocean, it's a pretty comfortable temperature and there's plenty of solar energy but you're shielded from the solar radiation. So, long term, your body will still work, assuming you can solve "the other problems."
Of course, the down-side is that there's nothing to stand on and probably more importantly, there aren't many useful materials to work with besides tons of carbon, oxygen, and nitrogen. Not much hydrogen there, so not much water, which probably is the biggest problem. One of them, anyhow. Also, there's probably not a whole lot to do besides float (zoom, actually) around and slowly go stir crazy in your bubble.
But relatively speaking, it's way nicer than living in a hole on mars where you'll slowly die from gravity sickness, or radiation poisoning, or whatever.
Actually, the cloud layer at that level is mostly sulfuric acid, from which you can get your water. It also means you need to be in a hazmat suit when you walk outside, but that's still a step up from everywhere else, where you need a bulky pressure suit instead.
Whether it is really possible, is a different question, but after you have an atmosphere, you could have engineered microorganism processing the soil etc.
(Turns out there's a region in Antarctic with them too, so we can always test things there.)
We have converted most of the land to agriculture and released maybe trillions of tons of greenhouse gas in the atmosphere, there are 8 billions of us working on it. And what did we do? Increased the global temperature 2 degrees? Made the sea level rise a couple of meters?
It may be bad for us, but compared to terraforming a planet like Mars, that's nothing, and we have the entire humanity industrial complex to do it while on mars, we need to build everything, starting from a hostile environment.
The advancements required to arrive at modern LLMs and the tech needed to get humans safely to Mars or live safely on the Moon are orders of magnitude in difference.
Keeping humans alive is hard.
Of course you’ll probably have lots of side-effects.
NASA has proposed using "synthetic biology to take advantage of and improve upon natural perchlorate reducing bacteria. These terrestrial microbes are not directly suitable for off-world use, but their key genes pcrAB and cld...catalyze the reduction of perchlorates to chloride and oxygen" [1].
2) If you have a source of hydrogen: water. Bonus as you don't have to make the dome hold pressure. A layer of water of the right depth will generate the force needed, the structure only needs to keep itself level. The only pressure holding is outside that, enough to keep the water from boiling. And, well, it's water--if it's hit by a rock that isn't too big you'll just have hole in the top layer, easily fixed. The same general idea would work on the Moon but the water is far from transparent if you pile up enough of it and you need a lot of hydrogen.