Arduino released support for Raspberry Pico, Arduino Portenta and other boards. The library use mbed as background. Please can you support them?
Portenta is already supported with the core version before that (Releases · platformio/platform-ststm32 · GitHub), Raspberry Pi Pico integration is already tracked in Please add support for RPi Pico (RP2040) · Issue #3805 · platformio/platformio-core · GitHub. But yes ofc an update would be nice.