I want to know if mod's advancements get the same treatment as the vanilla advancements, I know that Triumph exists but the required mods link me to 1. unresponsive pages 2. insecure pages.

I really want to know this so I can add it to the modded game I have.

All mods that use the Advancements systems will work with this mod. This is basically a visual and interaction overhaul the backend is just Minecraft. So as long as the mods don't do anything crazy it will work.