PF2e reduces all buff times to ten rounds. If you did that and made combat buffs cause aggro while also nerfing the power level of a lot of the concentration options you could get something working.
You could also have upcast effects like Web cast as a fourth level spell or Faerie Fire cast as a third level slot doesn't require concentration. Maybe a feat or metamagic thing where for 2x spell level sorcery points you could cast a concentration spell without concentration.