a scrim close to the talent gives the best diffusion, but I had no scrims with me and I had to take the interview with a decent lighting under an emergency setup. I don't use softboxes (basically because they diffuse very little and stay too close to the source and away from the talent) for a key in particular. Sometimes (in lighting) the simple things end up to be the best things. A still photographer was shooting in the next room with a white umbrella and that gave me the idea.
A 45 inch white umbrella shot through as far as possible from the source (on the same stand) gives a diffusion close to a full size scrim. OK not the same but close. 1 stand, 1 umbrella clamp with a stud and a key is ready.

this clamp for example:
https://www.bhphotovideo.com/c/product/838894-REG/impact_ca_108_swivel_umbrella_adapter.html/BI/2855/KBID/3801

Now I'm seriously looking for some 10 inch umbrella extension to bring it even closer to the talent and keep the bank at a safe distance.

for sure diffuses a lot better than any panel or softbox.