In the 1.12.2 edition, whenever I die and respawn, time resets back to 0, regardless of what time of the day it is. I removed all my other mods, yet the issue still persists.

Yeah, that was by design, so that you start your new spawn in the morning, and have a full day to set up protection for the night.

Ok, but is there any way that I could remove that function so that time does not reset? I couldn't seem to find the config option for that.

Unfortunately, it doesn't look like. I'm not actively working on Iberia, but if you or someone else wants to fork the code and make changes, you're absolutely welcome to. If I come back to it at some point, I will keep this issue open and include it in the work I do, but it's honestly not on the radar right now. For you, or someone else, the code you'll want to modify is in https://github.com/rockhymas/iberia/blob/master/src/main/java/com/gibraltar/iberia/challenge/SpawnChallenge.java.

I don't really have much knowledge in Java, so which part of the code should I alter in order to do so? I'm pretty sure it's between lines 211-226, unless if I should remove the whole thing by itself.

Yep, that would be the thing to remove.

Ok, thanks. I just created a new pull request. How do I install it to the Iberia file for my Minecraft mods?