New country, a new beginning
You can't make a silk purse out of a sow's lug. The recurring crises here make clear that Northern Ireland is a constitutional sow's lug that a constitutional silk purse can't be made out of.
A federalist would write off Ireland, north and south, into the history books as a constitutional disaster zone and start afresh with a new political philosophy, a new all-Ireland party with a new flag, a new name, a new platform and a new anthem.
Practical, concrete suggestions for this are with the SDLP for their consideration.