a basic millenium flacon is pretty simple. A flattened sphere for the body, cylinder for the front roundy bit, dimple on the top.

But if you're trying to duplicate what you can do on a package you know well in openscad after a couple weeks - you're just going to get frustrated.

You need to start with simple things. I find that the more I use openscad the more I learn and the more I can actually make it do.

But it's not a program where you can just leap in at the deep end.

Start with differences and unions. Then add variables, loops and modules.

The best way to learn is to build a simple model - a rocket for example ;-)
And keep tweaking the script as you learn different functions.

I reckon I can probably get the rocket script down to about half a dozen lines of code eventually and make it fully parametric.

And for the record it prints great too - used it to test a cheap roll of white pla.

But I do think you're trying to get too complicated too quick.