Upgrading memory on HP OMEN 16-c0500na 16.1" Gaming Laptop - AMD Ryzen 7, RX 6600M, 512 GB SSD

When I run GTA 4, it says I'm using 450 out of 512 or thereabouts GB?

So to ease the burden on the machine (as I'm going to be running GTA 5 shortly), I figure best to upgrade.

Yes storage.

I'm definitely going to have to get someone to do this for me.

The thought of opening up and potentially destroying my new machine positively unnerves me.

I was thinking I'd just buy the storage off amazon, then get the local technician to install it, but what storage is exactly fitting to this HP Omen?

Any specific M.2 ssd fitting/brand-name for that model of HP Omen?

Do Omen recommend a HP specific brand to use?

With the additional storage, the game itself will be able to make use of that to run faster, right?

As in, it's not for "storage" exclusively?

Does external-enclosure means what I think it means? (a usb'esque external attachment).

You need a clean install for ADDITIONAL storage?

I guess cause they have to integrate with each other or some-such?

Other thing, would adjusting graphics settings in GTA 4 effect storage?

As in this machine as 16 GB VRAM with the GPU, and 512 GB storage, but in the in-game graphics settings it's saying "400 out of 512 GB in use" and that varies according to how I tweak the graphics settings up or down;

Texture, distance, water-reflection, etc.

Would storage really be implicated for tweaking in game graphic settings?