Hi! I totally understand where you're coming from on this my hair is down to below my waist now and its a mission to curl and get it to stay curly!
I happened to get some advice from a few hairstylists and these tricks really helped.
First GHD has a product called curl hold spray, it costs around R180-R240 depending where you buy it, but it lasts forever! It isn't quite like hairspray but it basically helps the hair curl, locks the curl in and helps it to stay put. You don't need to use heat protector either since it has that built in. My curls last till the next day when I use it which is great since before it only lasted an hour or two max

I swear by this product
Next, when you're curling its all about technique. It seems natural to keep turning the straightener in order to get the hair to curl, but that will create waves and could burn your hair. The way to create bouncy curls is to twist not more than three times, then glide the straightener down the rest of your hair without turning it, this will get you that perfect ringlet curl.
And the last tip I have seems a bit obvious but its one of those things that I always forget to do. if your hair doesn't stay curly for long spray a little bit of hairspray in just after you've curled it to keep the curls in place for longer.