Had a major corruption in the IDE. Uninstall-reinstall did not work, had to restore from backup drive.
Anyway the Solution:
Find:
******** is users name etc.
OSX- /Users/********/Library/Arduino15/packages/esp32/hardware/esp32/2.0.0-alpha1
Open "Boards.txt"
Edit lines for each relevant dev board type using CH340 chips C3, S2 etc, set from "false" to "true".
esp32c3.serial.disableDTR=true
esp32c3.serial.disableRTS=true
Save the file and restart Arduino IDE.
RTS/DTR will stay HIGH by default.
Same for Win10.
Find, ****** is your user file name:
C:\Users******\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.0
Open the "Boards.txt" file and edit the lines from false to true:
esp32c3.serial.disableDTR=true
esp32c3.serial.disableRTS=true
Save and restart Arduino.
The C3 and S2 dev boards can now use the serial port for debugging.
Cheers