The local Apple Store's are getting various configurations of MacBook Pros for their inventory, but they get purchased very fast. If you want to find one locally then you simply need to re-check often. They don't receive these every day, and they don't necessarily know ahead of time what they might be receiving in their daily shipments, so you have to wait until they update their inventory as they receive them.
I'm watching the 14" availability at my closest Apple Store and this is what I am noticing. I'm sure it is similar for the 16".
I went through the same process when I purchased new iPhone 13 Pro Max recently, and was able to purchase within just a couple of days after I started checking regularly.