How is the Target Hash determined? So, I understand how the amount of leading 0's are calculated, but how is the hexadecimal that come after the leading 0's calculated? For example, the previous mined blocks hash was
000000000000000000084bc771b929b0780276b1c31cec10a96921b1e53b970a but how was the 84bc771b929b0780276b1c31cec10a96921b1e53b970a after the 0's determined?
I saw this answer: https://bitcoin.stackexchange.com/a/36228/110284 but I'm not gonna lie, I didn't understand it.
I think you're confusing a few things.
A SHA-256 hash is a single value that is 64 hexadecimal characters long. This hash can be seen as simply a very long number.
A target hash in cryptocurrencies is the maximum value that a successful block hash should be. Miners are aiming to generate a block where the hash, when seen as a large number, is a smaller number than the target hash.
The entire thing 000000000000000000084bc771b929b0780276b1c31cec10a96921b1e53b970a is a block hash. It is a SHA256 hash, and just happens to be a number that contains a lot of zeroes.
If you want to see how the block hash is calculated, take a look at this article: https://en.bitcoin.it/wiki/Block_hashing_algorithm