Dear @silvanrehm, thank you so much for the honest feedback! We appreciate it! 
Yes, we know that our community integrations are not ideal. We currently don’t have official support for STMicroctonroller products and ststm32 development platform serves a demonstrative character. Official integrations are listed in the PlatformIO Registry.
We will contact STMicroctonroller and work together on improving the developer experience for PlatformIO/ST customers.