Oh yeah, 100%! You don’t need a preorder app if that’s all you’re trying to do for now. 
Note that it may not work well since the primary issue seems to be that the order isn’t flowing through to your warehousing solution even with it being a regular order. But you can try this out and see how it goes.
In Flow, you’d set it up as -
- Use the “When order created” trigger
- Add a “Wait” if you’d like - for however long
- Add a condition to check if the order has a specified tag
- Run the action - Hold all fulfillment orders (and add a note)
Let me know how it goes!