Howard Miller

Ubuntu 24.04, by default, provides PHP 8.3. Moodle 4.1, however, does not support PHP 8.3. So you have a problem straight away.

It's possible to install older versions of PHP but you need to add a suitable repository. The usual is https://launchpad.net/~ondrej/+archive/ubuntu/php. There are plenty of examples of how to use it if you Google.

Alternatively, install the latest version of Moodle (4.4) that *does* support PHP 8.3.

It depends what you mean by "no longer have access to the course". If they don't have access to the course (you unenrolled them, the course is hidden or whatever) then they can't see the grades. If you don't have access to a course then you can't see the grades. I think that's logical.

 

If you want your users to have access to grades in a course, they need to stay enrolled. You may need to devise a more restrictive role for them so they can no longer do whatever it is you don't want them to do. 

It's definitely part of core Moodle - https://github.com/moodle/moodle/tree/MOODLE_404_STABLE/grade/report/grader

I'l move this to the Gradebook forum.

It's a bit of a classic - "It's not Moodle; it's the way the Internet works"

Sure... see Moodle_migration