If your external hard drive is fully disk encrypted, is it normal that when you connect your drive to the computer, it doesn’t show up where you normally find all of your connected devices, that i’ll only show up once you mount it and decrypt it in VeraCrypt? Is that a good thing?
Yes
u/MeCJay12 summarized things well.
You have to supply a passphrase, PSK, token, or 2FA to decrypt.
Consider full disk encryption as a large container covering the entire block device (HDD / SSD, etc). Inside the encrypted container is a filesystem which contains links to the locations of data (files) on the device. Veracrypt operates silently in the background. Once you supply correct authentication, the filesystem becomes visible to the kernel, is autodetected, and can be mounted.