@lbernstone: You are right: The settings of the "USB CDC on boot" flag were different in my two installations. Unfortunately I can no longer find out, why they are. Most likely it is, that I have changed one of them some time ago and forgot about it. Now I even better understand the documentation of...

I'm running an identical sketch for the ESP32-S3 twice: Once from the Arduino IDE v1.8.19 and a second time from the Arduino IDE v 2.1.1. The results in terms of "Serial.println(...);" statements are different: Running from the v1.8.19 IDE, I get the results from "Serial.print(...);" statements only...