Currently, LoraLoaderMixin supports Koha format for older SD models. However, with the change in architecture and the two text encoders, the process is now different for SDXL.
I don't feel overly confident implementing this myself, but I have made an SDXL lora (Lycoris) that loads up fine in comfyui to test with:
https://civitai.com/models/111031?modelVersionId=119726
Cheers,
Z.