I have 4a hair with some 3c. My trick for 2nd day hair is as follows:
Sleep with a satin bonnet or on a satin pillow

Use a water spray bottle or get in shower and wet hair till it s saturated. If u use water spray, wait 1-2 minutes to let water saturate hair. As u do, flattened curls will start to swell almost to their first day state. Do not touch. Just shake ur hair a few times.

Also my 2 best curl definers are Kinky Curly Custard (with the knot leave in underneath) and Hawaiian Silky Curl Activator. One is super $ and the other is super cheap ($4-$5) but they give the same curl definition and shine. Difference though is that u don't really need a leave in if u use the Hawaiian product. Plus your hair is not crunchy at all. But I find that with KC Custard, a little goes a long way, and the crunchiness is relatively minimal. Go heavier on the knot leave in and longer on the custard.