Need suggestions for 75-80° beer

Right now I have a stout going in my wine fridge but I have a 3gal carboy I would like to put to use. I won't be able to control the temps, so it would have to be a beer that can ferment at 75-80° (room temp in my house) without creating off/nasty flavors. I can't do the swamp cooler thing because I work 10-12 hour days and can't babysit it.

So far the only thing I have found that is good for those temps is a saison. The only thing that is kinda preventing me from making it is the description I read in the BJCP, for flavor is states "a low to moderate alcohol presence and
tart sourness". I'm not into beers with a "tart sourness".

So what else is there that I can brew that would be maybe 6-7% abv, easy to drink and taste great?

I have used the swamp cooler method and have successfully maintained temps around 70-72F with temps in the 80s. I checked it in the morning and again in the evening. If the temp was high I changed out the water and added a bit of ice. I also wrapped a towel around the fermenter which helped insulate it a bit more.

Alternatively to a swamp cooler (tub+ water + ice blocks +wicking shirt+ sometimes blowing fan), you can make a fermentation cooler. I bought a 60qt igloo blue ice cooler ($27 Walmart). It's a tall square rolling cooler.

The lid is removable. I cut it to fit my 6 gal ale pail bucket. Guys with carboys can cut less and just cut a small hole for the neck. Others just remove the lid and use a towel, or buy foam board and fashion a lid. This is nice because the cooler can be actually used as a legit rolling drink cooler when needed

I actually get far too cold if I use the shut lid and multiple frozen 2L bottles (low 50s). I've found with a towel over the cooler and one 2L ice block I can get into the low 60s (beer temp) if I change the ice block twice a day. I don't need temps that low, so I use one 2L and change it once a day. My house in Gainesville, fl with this current hot weather is 77*. I will wake up to it around 68 and add a 2L in the morning. This will drop it around 62-64. By that night it might be 64-66. By the next morning back to 66-68 and I can exchange 2Ls. Colder temps like we have coming to Florida this week means less exchanging. The one disadvantage is I am swinging temps about 5 degrees daily. Though I am keeping in my optimal yeast temp range, my temps aren't consistent as desired. I've been experimenting with also adding water to the cooler which is helping to minimize the temp range swings.

For the record, OP, I just had a Hennepin (saison from Ommegang). I would not have described it at all as sour.

Citrusy, a bit sweet up front, finishing dry... very much similar to many Belgian styles, but with a little pleasant funkiness. A nice beer, to be sure, but not at all sour.

Some saisons have a tartness to them. Some don't. And I'd call it tartness like the tang that some wheat beers can get (although not all saisons use wheat), I wouldn't call it sourness. There are certainly ones that are actually sour, but I've never made a sour saison without intentionally souring it (ie something other than just yeast)

Belgian Yeast strains tend to like those temps. So, yes a saison would be a logical choice. You could also try a Belgian Blonde or Beire De Garde with a belgin strain. Belgians at those temps tend to be a bit funky with the esters and phenols. WLP530 is a belgian strain that is supposed to have lower amounts of spicy, fruity flavors. You could try it, but 75-80 is technically higher than optimal for that yeast. Maybe try a classic saison and hop it with some NW American hops to see it it goes.

So is it the yeast that causes the tartness or an ingredient? Sorry for the stupid questions, I'm still really new to this.

Only brewed 4 batches so far, first two were failures due to not cooling down the wort enough before pitching yeast, 3rd turned out great, and the 4th one going now is I believe a stuck fermentation.

Depending on the ingredients, it can be both. Outside of adding bugs/sour mashing, some folks apparently use acid malt in the grain mill or add lactic acid. A little bit lowers mash pH, any more and it can taste sour. But saison yeast can definitely give some mild tartness depending on the strain. Wyeast 3711 is probably a good bet for you since it seems to A) be milder than other saison strains in terms of flavors B) be less picky about its temperatures and c) not have the problems other strains do with properly reaching a gravity low enough for the style (namely because it's less picky about temperatures, others can crap out way too high if you don't have the temps exactly right)