Should I abandon Microchip (Atmel) Studio for programming AVR microcontrollers?
PlatformIO, an extension for VSCode, allows not only to program Arduino code, but also plain avr-gcc including the upload with an USBasp programmer.
A student of mine showed me how to configure platformio and I had to find out that the avrdude which comes with platformio is somewhat limited in its functionality.
The necessary changes to the project's platformio.ini which I used in the video are:
[env:ATmega328P]
platform = atmelavr
board = ATmega328P
board_build.f_cpu = 1000000UL
upload_protocol = custom
upload_flags = -pm328p
-Pusb
-B4
-cusbasp
upload_command = "C:\Program Files (x86)\AVRDUDESS\avrdude.exe" $UPLOAD_FLAGS -U flash:w:$SOURCE:i