How to replicate this behavior of the multiparm block and folders in HDA ?

i.e, distribute blocks into folders as the number of blocks increases ?

this is most likely not possible in HDAs at this point, since if you promote that exact multiparm it will be just a regular tab multiparm

COPs have a lot of custom UI widgets that are not replicable in HDAs, like Levels or Colormap COP sliders, Chroma Key or Color Replace COP color wheel or Convolve COP single row float 9 parms