They look well within the normal range of shapes to me.

I appreciate you letting me know. Thank you.

It’s trying to conserve moisture in the leaves.

You want the edges to curve downwards, right? So the leaves are fuller?

Basil leaves fold inwards like that when a) it’s consistently too hot, sunny and/or dry, or b) the plant is about to bolt.

Your plant has already bolted, so it’s focusing its energy on the flowers. The leaves will likely stay that way - and any new leaves will be small - unless you cut it back severely to get it to refocus on growing leaves. It doesn’t always work, though - especially if you’ve already let it go to seed.

It’s pretty normal towards the end of the plant’s growing season, but it is possible to get the fuller leaves back again.