Slight chance of finding it if you notice it's missing fast enough.
FindMy only finds the charger, not the headphones out of charger, but you can make it play a sound.
You can buy a replacement for about 50% of the price of a new set (complete with charger case).
One night I dropped my case as I crossed the street to my building. I grabbed it off the ground without paying attention, both buds had fallen out.
In the morning, I picked up the case and noticed that it felt light. Find My reported both buds as having been seen outside on the sidewalk, one last seen four hours ago, the other six. I ran downstairs and outside to find them both smashed by car traffic.
Another time a bud popped out of the case while passing through the TSA X-rays (yes, I have lousy luck with these). I was able to pinpoint the direction with the app and make it plays sounds, but the agents were unable to dig under the rollers and get it out.