I have an umbrella that is a shoot thru or shoot into when you put the black covering on it I think it's a 42 inch but I'm not sure and I had the black cover on.
I haven't tried shooting thru it.
I also tried with my strobes that have a large softbox. Again I'm not sure on the size I think upper 40 inch realm (they're not mine I'm just indefinitely borrowing them from a friend so I'm not sure on siZing.
If your lighting is still harsh with an umbrella, you have it way to far back. The closer it is to the subject, the softer the light will be.
Placing the umbrella up close and at a 45 degree angle at head height or slightly higher is a good starting point..then adjust from there. Always put the light to the side the nose is pointing to.