Opening that link did work, actually. It gave me a warning that the website wasn't secure, but I could, indeed, access it via the IP address. I did a test with this, using ping to retrieve the IP addresses of each problematic website and attempting to enter them.

Mega.nz (66.203.127.12) redirected me to the name address and returned the same error as usual. Neocities.org (198.51.233.100) returned 404, as did theameliamay.neocities.org (my website; 198.51.233.2). Quad9.net (216.21.3.77) gave me a privacy error, but allowed me through. Rt.com (207.244.80.166) redirected me to the name address and returned the same error as usual. Torproject.org (116.202.120.166) just sends me to a page titled "Welcome to web-fsn-02!" which isn't the usual website.

This gave me the idea to manually add the addresses to my hosts file (which is a bit dangerous), which worked perfectly for nearly every site — with the only exceptions being rt.com, torproject.org, and mega.nz.

I can connect to rt.com, but it doesn't load properly, while torproject.org returns the same error as usual. I assume this is for the same reason it didn't work properly when I attempted to make a direct connection. Mega.nz loads just fine but won't let me through the initial loading screen. I've removed the three problematic websites from my hosts file in order to not cause any issues, but left the rest.

I'm not sure why this is the case. You would assume my DNS server can't link the host names to the IP addresses, however, I've tested around 5 DNS servers by this point and none of them can get through, not even DNS.watch. Since I can connect to them via editing my hosts file I'm fairly certain there's not an IP block. Perhaps my ISP is somehow preventing every DNS server from providing my computer with the correct address?

Thanks a lot!