It's nearly impossible to change your hair's natural texture without heat or chemicals.
I highly recommend embracing
your hair and letting your hair do what it wants to do
. Once you stop fighting with your hair and accept that it will never look your fantasy hairstyle, it will become so much nicer. If your hair wants to mimic a wild lion's mane, let it do that.
Alternatively, you can try twist outs, braid outs, or doing roller sets, but I never had much luck with those techniques.