If I use the personal mri and eeg to build a head model (20484 dipoles), how can i extract the dipole numbers under the dk template?

If i use the default anatomy, it has the infomation of the DK altas. However, when i used the mri and eeg data to build a personal head model (the model has 20484 dipoles) and export the "spm_cortex_20484V", i found that the exported data has no infomation of DK altas.
What can i do to get the altas in this case?

The DK atlas in the default anatomy was generated by during the MRI segmentation (performed with FreeSurfer in that case).

You can perform the MRI segmentation with CAT12 or FastSurfer, both can provide the Desikan-Killiany cortical segmentation.