System Stats Memory RAM (with Cache) vs Memory RAM (No Cache)

I dont quite understand what the above mean?

My Vultr VPS has 2 GB RAM.

After a default Centos 7 Install + CWP (nginx, apache + Varnish) and nothing else other than I am compiling php version 7.3.3 in the background, what does the following actually refer too?

How much of my Vultr Instance 2 GB RAM is actually being used?

Memory RAM (with Cache): 1.48GB / 2GB ( 74%) [DC]
Memory RAM (NO Cache): 0.44GB / 2GB ( 22%)
Number of processes: 104

My assumption is that the one i should be keeping an eye on, with regard to this provisioned to become a small webhosting server with shared websites, is Memory RAM ( No Cache)?

This is a too extensive discussion, too beyond CWP.
You can check this discussion about the subject:
https://serverfault.com/questions/597115/why-drop-caches-in-linux

Basicly, drop cache is not a good practice to free up RAM, it causes the kernel to look for files on the disk rather than in the cache which can cause performance issues. It is needed only in a needed exception situation. Periodically, kernel will clear the cache when the available RAM is depleted.

Regards,
Netino