I have a DL360 G8 rack server, and I decided to self host my website on it, (on a virtual machine of course). The server itself is pretty kitted out, with dual xeons, Raid 0 drives, and 32 GB Ram (6GB Allocated to the VM). The Server is running Windows Server 2019, so is the VM hosting the site. It used to have a load time of about 5 seconds, but recently it has been going as high as 30s. I checked the plugins, they aren't the issue. I also installed a caching plugin, which did next to nothing. I use Cloudflare DNS, with all my A and CNAME records proxied through cloudflare. When I checked the speed on pingdom.com, it showed that a massive amount of time was spent "Waiting", which it described as the browser waiting for the server to deliver data. How can I speed up my site? Again, I understand that using a hosting service may be faster, but my site was working just fine before, so please don't say that.
EDIT: Results from webpagetest.org: https://webpagetest.org/result/210226_Di3Y_801c04c6f14d2c9241699f7a9f643255/