Right now for "Title" the release group guideline says
"See the guidelines for recording and release group titles for how to enter the release group's title."

That's a bit confusing since we already are on the release group guideline page.
It links to Style/Recording_and_release_group_titles which then redirects to Style/Titles

It's not really clear how the release group should be named if the releases are named differently and there is no most common variant or "more official" title like the recording guidelines says.

It seems it was supposed to say something like

The title of a release group should usually be the title of its individual releases, removing release-specific Extra Title Information added due to Disc Number Style. In the case of re-releases with different titles, the principle of Consistent Original Data should be applied to choose the release group's title from one of the linked releases.

per old style proposal
https://wiki.musicbrainz.org/User:Jacobbrett/Release_Groups#Title

From my interpretation release specific information should generally be removed from release group titles and the most common (official) release title chosen, alternatively the original title.
And for bootleg release groups a standardized name should be used per Style/Specific_types_of_releases/Live_bootlegs