Hello again,
I tried compiling using the CLI with the clean option enabled but no success. No redefined macros in main.c (MQTT_TLS.ino).
I used this command:
arduino-cli compile --fqbn realtek:AmebaD:Ai-Thinker_BW16 --clean --verbose MQTT_TLS.ino
This is the output (sorry, it is too large that isn’t allowed in Pastebin).
Still, the uploaded binaries (using CLI) are the same and no changes are effective. I guess that what @xidameng says here is related.