The Raspberry Pi Pico SDK works only on Raspberry Pi OS.
The Pico SDK works on many different operating systems, including Ubuntu, Debian, Windows, and macOS.
The Pico SDK uses cmake for C/C++ applications
Debugging with gdb requires connecting the SWD pins on the Raspberry Pi Pico using jumper wires.
True, the SWD pins must be used for interactive debugging. This may require soldering headers to the Pico board if the board didn't arrive with headers installed on the SWD pins.