@Bob_Le_Schoenthal - In the coming months, there’s going to be a change to project memberships (you’ll be able to add teams as well as individuals) that might make this a bit more challenging (but not impossible). See here for more on that upcoming change:
I do agree that it would be great to bulk update project-level field data would be extremely helpful (when I need to do this, I just run a script that calls the API, but that’s not a viable solution for most users). I couldn’t find a relevant topic on this, so feel free to create a request in the Product Feedback channel!