Hi @derekkruzicki ,
Is the 'Req Number' column a lookup column for the ID column? I recommend that you create two flows to increase the speed of the flow, and the first flow runs only once, getting attachments to tables that are not currently modified. The second flow is triggered when the SP's item is modified, and only the currently modified Item is updated.
My test:
"test0927" is equal to delivery list which has a look up column.
"test08188" is equal to requisition list which has attachment.
The first flow: Get items connects to delivery list which has a look up column.
Get items 2 connects to requisition list.
1)

2)The value is about the Get items 2.
"lokupID" is the look up column in "test0927".

3)

The second flow:
1)

2)

Hope this helps you!
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Best regards,
Rimmon Li