Would be absolutely necessary for Devs to implement disabling sub-Portfolio Item, and being able to move it somewhere else.

Everything is in the title. 
And also being able to duplicate portfolio. I Don't think those things would take a long time to implement and yet they are crucial. 

I'd like to help, but I don't really understand what you're trying to do, or why you're using a portfolio page if you don't want portfolio items?

Well, let's say I have a portfolio. It's live. 
I would like to add a project, but i can't disable a page in the portfolio while working on it.

Well, that's an easy answer! You can duplicate a portfolio item in the item settings, scroll down, click duplicate.

Hiding a portfolio item is as simple as adding this to your Custom CSS, and tweaking the portfolio item URL to end with -draft

// Hide Draft Portfolio
div.portfolio-grid-basic .grid-item[href*="draft"] {
  display: none;
}

Hope that helps! Give me a thumbs up if it did, thanks!

17 hours ago, makeartnotwar said:

I would like to add a project, but i can't disable a page in the portfolio while working on it.

This was answered by @tuanphan in 2021: