if you want to use vrc to warudo exporter first you need vrc not vrca
use AssetRipper to deflate vrca (because vrca basically a renamed filetype for unity AssetBundle)
use FACS_Utilities to fix broken stuff
do a bit more tweaks until the avatar is upload-ready for vrchat, now you converted vrca to vrc, and you can use the tool you linked to convert it to warudo