Looking ahead to a 32-team league in 2028, or whenever, I can envision:
Other league: four against "natural rival", three against everyone else, 49 subtotal.
Same league/other divisions: six against each, 72 subtotal.
Same division: 13 against each team, 39 subtotal.
That would make for a total of 160 games, which would provide a couple of extra off days for Players and one less April home games for teams, so I think both sides could agree on that.
They could go whole hog retro, cut down in-division games to 11 per opponent, and make the 154-game schedule the ultra-traditionalists continually pine for, but I don't think either side wants that many fewer games, necessarily ... unless they can make it up in expanded playoff revenue that accrues to both all teams and to Players, which feels unlikely to me.