The Atmel MCUs used in the 16MHz Arduinos don't have facilities for in-circuit-debugging
I don't use the Arduino IDE for editing, only for compiling and uploading code. I use the Geany editor
I think you would most easily get an appreciation of the Arduino system by getting an Uno and working through some of the many examples that come with the Arduino IDE and the many online tutorials.
Be careful not to confuse an MCU with 2k of SRAM with the programming space available on a PC.
Before the fight they are officials for Arduino LLC, now only God knows, and that's not even sure!
Note this excerpt:
1.5 UNAUTHORIZED USE.- Arduino Srl products are not authorized for use in safety-critical applications where a failure of the Arduino Srl product would reasonably be expected to cause severe personal injury or death. safety-critical applications include, without limitation, life support devices and systems, equipment or systems for the operation of nuclear facilities and weapons systems. Arduino Srl products are neither designed nor intended for use in military or aerospace applications or environments and for automotive applications or environment. customer acknowledges and agrees that any such use of Arduino Srl products which is solely at the customer's risk, and that customer is solely responsible for compliance with all legal and regulatory requirements in connection with such use.
Object-Oriented and "High Performance" are IMHO 'mutually-exclusive'. Typically as a result of
"Spaghetti-Classes" ( analogous to "Spaghetti-Code"), but Good Luck, I won't dissuade you any more.