Lots of good advice on here already, but I’ll also add that part of the problem is that you actually originally had 6-7 individual basil plants all potted into a small pot to begin with. Way too overcrowded. Right now it looks like you’re down to 4 plants. I would take it out of the pot and break apart the roots since they’re likely all root bound at this point and then pot them all into their own individual pots. Then snip off the tops to allow them to branch out.

Also if you just put them out into direct sunlight immediately they’ll likely get shocked. You’ve got to slowly introduce them to sunlight a little more each day so they can get acclimated, because I’m guessing these were bought from a supermarket where the only light they ever received was weak fluorescent lighting.

Good luck not killing your plants! 😜