Item availability has been really random at most grocery stores lately. It's something I took for granted most of my life and has been difficult to adjust to. Usually we make meal plans for the week, then go buy what we need. Now I have to go to several stores, assess what meat or produce is available and figure out on the fly what meals we can make out of it (hopefully remembering all of what I bought at the last store).
I can't imagine how hard it is for services like Instacart to handle. Same chain of grocery stores a few miles away from each other often have wildly different items in or out of stock on the same day.