You don't have to chop it all off by any means. That was just my personal opinion 'cause I'm lazy, which is why I don't buy almost dead plants either. But if you do decide to cut, leave about 4 or so inches of stem from the soil surface. It'll backbud making each stem branch 2-4 branches. It wouldn't take that long to grow back (and it would) and it would be fuller and brighter. And those leaves that you cut really short, if they are adult leaves, chances are good that they'll be short for ever more. Now, if the plant seems pretty happy right now, you can just leave it as is, and keep a close eye on it. For all I know it could bounce right back. Some plants can have a crazy will to live. Whichever you choose, I wish you the best of luck with this plant. Perhaps your thumb is greener than anyone knows.

I am new to gardening myself and my basil was doing the same. I live in RI and watered every 2-3 days and it looked like I was leaving them in the sun to long but was told I was watering them to much. (Honestly I dk how people can tell.) What I did though and it has improved my plants a little is water every 2-3 days depending on the heat and I started putting them in areas where they had full sun for only 6-9 hrs a day. Once they bulked up a little I put them in brighter spots. This did not fix the problem completely but it did help a lot. Hope it helps you.

This happens to mine all the time. Brown spots or the whole leaf turning read before crinkling away. Varies highly from plant to plant. It doesn't seem to be a problem as long as some secondary leaves have had a chance to come out. Your mileage may var.

Are they near the house where a reflection could hit the leaves and magnify a burning sun ray? I would maybe keep them in the shade but introduce them to sun little by little.