If you are at 25 heart level today, that's only 1000 azerite to get to 26. You can do one emissary and get a level and a half, not to mention the 4 quests that you do to complete the emissary. I just leveled a brand new alt to 120 and in about 3 days its already heart level 32 without any real effort. And I really mean that. I don't even do islands on that toon.