When they are referring to "Unflavored Gelatin" typically they are referring to the Knox product below. Without the unflavored gelatin to harden up your candies, they will simply be like normal Jello.
I’ve used this sunflower lecithin it’s quite a bit of lecithin (one pound) but I’ve yet for it to go bad on me, I still infuse with it monthly and after two years am finally just about through with the bag.
Right on, juice was the only thing I found besides citric acid that changed the texture. For flavor try this, I use the cherry one.
https://www.amazon.com/Hobbyland-Flavors-Orange-Flavoring-Concentrated/dp/B07GT97GSN
I make 1 to 2 batches of gummies a week and got this down pretty good lol.