I was going by my memory of what I recall reading here about a year ago. And my recollection was that it wasn’t supported. I took that to mean that it wasn’t possible. But those two things should not be confused. The more I’ve learned about Playcanvas, the more I’ve learned that good information is fairly scattered and that what you think you know can easily be half-wrong or incomplete.
After doing some digging tonight, it seems like morphs are possible using the glTF loader but maybe not with FBX. (Emphasis on the “maybe”.)
But that may be out of date at this point in time.
I did find projects that show morphing in PlayCanvas, so it seems that it is possible. Now the trick will be to better understand the steps to get it done and find out how reliable the process is.