The ESP32-C6 requires the newer Espressif Arduino Framework 3.x.
You have to use pioarduino’s espressif32 platform to get 3.x versions:
platform = https://github.com/pioarduino/platform-espressif32/releases/download/stable/platform-espressif32.zip
The change from 2.x to 3.x comes with a few breaking api changes.
Pease read Migration from 2.x to 3.0 - - — Arduino ESP32 latest documentation
Afaik then the build-flag -DUSE_HSPI_PORT should fix this issue.
Please see ESP32-S3-LCD-1.28 display not working - #15 by maxgerhardt