The only card left for the GOP to play is push for ‘proportional’ allocation of electoral college votes in states like PA, etc. Otherwise they will be extinct.
The House reflects the feelings of the people currently, and is closer to the people (elected every two years, not six). The Senate originally was intended to reflect the wishes of state legislatures, not the electors.
Remember the red and blue voting maps, showing counties voting Republican. Even California had large red areas.