Of all the ingredients that have been on and off grocery store shelves and in and out of online inventory, yeast seems to be one of the more elusive. Those of us who are not invested in sourdough rely on commercial yeast any time we want to make a risen dough. Such a small ingredient, but such a large impact.
If you haven't been able to find yeast from your typical sources, inquire with your local bakery. Many are selling it, and so are restaurants, including some not necessarily known for bread. Even one of my favorite farmers market vendors has been offering limited amounts. When you do happen to land some yeast, it may feel like you've won the lottery. You may want to preserve the precious supply.