It might have been more work to convert the model for the RK3588 NPU, even if Rockchip provides an SDK and an automated conversion tool that should help (the SDK includes a simulator for the NPU, so the converted model can be tried on a PC before being deployed on a board like Orange Pi):

https://wiki.t-firefly.com/en/ROC-RK3588S-PC/usage_npu.html