Currently, the user is able to split the expenses over many dimensions via the Cost allocation in the General Recurring Journals, but this is slow for the user as sometimes he received an invoice that will be split over 4-5 dimensions, now he will record it on a general dimension then later he will allocate it, which is a time-consuming and repetitive task.

My suggestion is to configure it in the Chart of accounts / G/L Account add new section for allocation, like the deferral templates the user sets the allocation, and when he inserts the line he can just select the allocation code, then the system will create the required journals