Jira 7.8.2
Out-of-the-box - *no plugins possible*
I've created a templated Jira Project with Epics and Issues (and they're linked i.e. in the Scrum Board and Kanban Board's Backlog View the Epics Pane shows the links).
The ask: to copy this structure into target Jira Projects preserving the Epic+Issue links.
CSV export and import is possible, however if this is the solution then I don't know how to preserve Epic+Issue links as rendered on Scrum/Kanban Boards' Backlog Views.