أحسن الله إليكم We’ve studied in manhaj as salikeen that if money was inherited or gifted then this requires its own seperate year to pass before zakah is due on it. We also studied that it is favored to put all your money together and pay the zakah. Can you please explain these two scenarios?

Money you inherit or are gifted has its own year, starting from when it became yours, so zakah on it is due only when that year is complete. Paying zakah on all your money together when the first amount's year completes is better, because what has completed its year is paid on time and the rest is paid early, which is allowed.