WASHINGTON — Republicans have seized on inflation as a centerpiece of their campaign to take back Congress next fall, laying blame for rising prices on President Joe Biden and his congressional allies as voters express increased concern. But beyond blocking Biden’s wide-ranging social safety net and climate action plan — under consideration in the Senate through a process that would allow Democrats to pass it along party lines — how the GOP would tackle a notoriously difficult economic trend is less clear. Interviews with a half-dozen Republicans showed that while the party is not yet unified around a specific plan,...