RAM

First, get rid of Clean My Mac and check RAM usage. CMM is a problem, more than one really, just waiting to happen.

How is your RAM pressure? If it's all green, all is good.

You're getting a free replacement 16GB model? Waiting builds character my Mom used to say.

Macs are designed to use RAM; the more you have the more it's going to use ... that's why it's there. If you can run all your apps and RAM pressure is "in the green" your Mac is running as it's designed to.

The speed increase because of increased RAM will be negligible. Your drive, SSD vs. HDD is a main, and most often, determiner of speed. That and all the other compatible and optimized components working in concert.

AnasZeidat wrote:

And guess what, I have to wait for like 2-3 weeks in order to get the 16Ram one because its customized.

There's a couple of 16 GB RAM MacBook Airs floating around on Apple's Refurbished store (be sure to select the correct country). Ordering from there should be a lot faster, as those Macs are already built and just need to be shipped.

As already said by ku4ax, uninstall CMM.

Unused RAM is wasted RAM. If, after you uninstall CMM completely, you are seeing RAM pressure then we'll try to determine what is causing the pressure.