For a very long time, we at The Open University UK have used a custom theme over-ride to make other ID fields sticky. For us, we use Forename/Surname, hide email address, and show a Personal Identifier (PI) and OUCU (OU Computing Username).

Many courses have multiple graded items, so there is a lot of horizontal scrolling, and it would be useful to have a new feature to lock/stick/freeze these ID columns as a Moodle Core feature, so that we don't have to fix our custom over-ride every six months.

If we use https://school.moodledemo.net/grade/report/grader/index.php?id=72 as an example, note that the 'email address' column is not sticky/frozen/locked like names are:

Our initial suggestion is to contribute a 'lock' feature (exact wording to be decided) for ID fields/columns, making them locked/sticky/frozen. E.g. '[Unlock | Lock] ID field' as a setting option.

Locked columns would be unlockable, including the default 'Forename/Surname' column.

Font Awesome has both fa-lock and fa-unlock, which could be used to denote the column status beyond simple scrolling.

By default, you would be able to specific the default locked columns at a site (/institutional) level.