I thought I'd try an export of some of the prettier blocks. Though small, it also has 98 separate textures, including numerous normal, reflection, and metallic textures (I believe Sketchfab has a 100 texture limit). See https://skfb.ly/otYFs for another, smaller sampler.
Import to Sketchfab is easily done: export to USD from Mineways (select the JG-RTX textures first), zip up the USDA file and the corresponding material directory, upload this ZIP to Sketchfab.