What is the definitive platformio.ini configuration for the pico-w?

[maxgerhardt]

I’d say

[env:picow]
platform = https://github.com/maxgerhardt/platform-raspberrypi.git
board = rpipicow
framework = arduino
board_build.filesystem_size = 0.5m

See Using this core with PlatformIO — Arduino-Pico 3.6.0 documentation and available boards.