My understanding is that the Administrator role is handled differently from other roles. Basically, there is no set of permissions for the Admin role - if a user has that role, then TRUE is always
returned when they get checked for permissions. There is no matrix of individual capabilities for a user with that role.
That is, you cannot select an "Administrator archetype" and just remove a couple capabilities. The closest default role to what you're looking for is the Manager role, but that role usually does not have permission
to edit most plugins, for example, so you would need to significantly modify the role (Allow a lot of capabilities) to make it feel like an Administrator.
Consider that, if they had permission
to do everything
besides editing those two plugins, they would have permission to change their role and add that capability back. So, you could try to also remove the capability to modify roles, but if they need pseudo-Admin privileges, then this could hinder their ability to troubleshoot other kinds of problems. At this point, it is starting to feel kind of messy.
All that said, I am sure you are not the first person to need an almost-Admin or super-Manager, so perhaps someone else has a similar role preset they can share. I imagine such a role would require a bit of upkeep any time you upgraded Moodle or added a new plugin (adding new capabilities).
I don't want to tell you what to do, since I know very little about your situation, but if you intend to give them privileges to do anything else on your site (see user personal information, modify grades, delete courses, change sitewide settings, etc.), it's hard to understand what is so special about those two plugins, in comparison. If you could describe the requirement a little more, it could help put it in context
and possibly lead to a solution.