Just a random thought…
Why not implement an “unofficial supercup” with the winner of each league playing the winner of the national cup by scheduling friendly matches.
Since no neutral stadium can be provided there could be a draw to decide with team would play at home or play 2 games and consider the aggregate result.
It would be up to the managers to decide the best time for this (if any) so that it would not have an impact on their league performance.
Just to add some spice :D (sorry if this idea has been posted before).
Cheers
Ahhh… my day is once again divided in “ticks” :)