Problem Definition

The epic view groups all the issue without epic at the bottom regardless of their rank, so from there you have no way of actually ranking them below
in this case, some of his story without epics are ranked above other with epics and gets scheduled before
in the story view the ranking should match the scheduling result
now there is definitely no way to massively re-rank issues at the bottom from either view.

Suggested Solution

It would be a sensible improvement suggestion to be able to (with some care) let a user rank all issues without epic at the bottom from the epic view.

Workaround

From the agile board (as it lets you group select and drag-drop) to re-rank those issues without epic actually below those with an epic

Having a JQL with all the stories without epic (and only those) should be an easy one
then can attribute them to a 'later' or 'triage' or just temporary epic
then in the portfolio epic view if you drag&drop that epic at the bottom it will re-rank all stories below the other
other solution would be to add those stories to a release and set it in the far future / after everything else