Heltec boards are not well supported in PlatformIO since there is no support for the Heltec modified Arduino core. There are already some topics about that in this forum, e.g., https://community.platformio.org/t/how-to-use-the-heltec-wireless-tracker-esp32s3-sx1262-gps-lora-node-meshtastic-and-lorawan-compatible.