This achievement is currently impossible if you are level 80. The player level is too high to be afflicted by Fiery Veins debuff so it can not be completed. This issue was present during Dragonflight as well for level 70s, but a workaround existed. During Dragonflight, you were able to sync down with Chromie time to 60 on a max level character, which allowed you to be afflicted by Fiery Veins to complete the achievement. Since the launch of War Within, max level characters can’t go below Level 70 with Chromie time, which is too high for the content and causes Fiery Veins to be resisted.
Please allow for Fiery Veins to debuff level 80s and not be resisted otherwise this achievement, which is NOT warband-shared, will forever be unobtainable.