Right now unarguably; Mahomes, Allen, Jackson, Burrow, Love, Daniels, and Hurts plus if we include younger versions of Stafford, Rodgers, and Wilson.Define "franchise quarterback"
Simply listing the current ones would suffice.
I say the term has become meaningless.
Arguably; Nix, Lawrence, Herbert, Prescott, Goff, and Tua but they all have detractions.