We have several projects in Jira (> 10), with different configurations. Each project has its own dedicated team with its own settings (incluiding permission).
Usually only some people inside the team have Edit permissions (including Epics).

Issues in epic are created sometimes by the owner of the Epic, but sometimes also by other people, and ususally in different projects that epic belogns to.
But there is no way, how user (reporter) of the issue can add its issue to Epic that belongs to other team, even if both users want to link the issues (create Epic link).

Example:
User John is owner of epic in project A (John has edit permission in A project)
User Will is owner of story in project B (Will has edit permission in B project)
We don't want John to have a generic edit permission in B project and vice versa.

Usual situation is, that Will finds out that his issue is relevant to John's epic, John agrees with adding the story to epic, but Jira doesn't provide any possibility how to create the epic link.

Creating of Epic links should be based on Link issue permission rather than Edit permission.