convert 164K gifti to 36K niml.set

Hello all,

I am trying to convert the Brainnetome surface atlas which is in a 164k mesh and Gifti format to the 36k niml.dset format common to AFNI. I am new to surface analyses and find the multiple file formats confusing. My initial attempt was to use SurfToSurf, but this output a 1D file without node ROI value and a niml.M2M file which I wasn’t expecting.

Could you please advise on this overall pipeline from gifti to niml.dset while also changing the mesh density? Are these two separate transformation or can they be done simultaneously?