I have a group who wants to restrict viewing permissions to components (or a custom field by "sub type") while still giving Create and Edit access to the Jira project. Is this possible?
I have already suggested breaking out the content into separate Jira projects but I am doing my due diligence for the user.
No, it's not possible to do this.
You can only restrict issue visibility by using security levels. You could set up something convoluted about setting security levels with Automation, based on other fields, but it is complex and unwieldy, and the complexity usually means mistakes will happen and people will get to see the wrong thing. I'd always push "separate projects" over "automated security levels"