@Rubén-0
Hi Ruben, iPhone user here!
Was out running with AirPods 4 (paired with my new Suunto Run watch) before stating the run, and yes, the watch do give either a vibration or beep if the connection is lost or reconnects, and will show it on the watch-face!
It happen a couple of times in my 5K run, so i guess we have to expect that it can happen.