it working in other applications is no guarantee that the UVs aren't flipped - marmoset certainly handles it correctly. I don't personally know if arnold/maya does
Can specular/glossiness textures be exported from Substance Designer in a way that would work with Vray/Arnold/Clarisse? I can see the options when exporting from Painter, but in Designer specular/glossiness template says "This workflow is not compatible with offline renderers such as Vray or Arnold." Is there a…
Arnold would be able to do this. Arnold isn't a third party rendering engine anymore - it's the default maya one. You could also use mentalray, renderman, or vray.