There is no any method to limit the backorders (unless you use custom development, but us we don't offer this service you should contact a developer).
In any case, something you can try is to use our premium add-on ATUM Multi-Inventory. The main feature of this add-on is the possibility to sell a single product to different parts of the world, but it has another features that could be useful for you.
So, you can create two inventories for your products. One with the limit backorders items so you can sell the product from this inventory when actually there is no stock, and the other one with the stock that arrives to your warehouse. So you will be always able to track the stock of the product. You can write off the limit backorders inventory when you have real stock to sell.
I leave you here the documentation of the add-on where you will find useful info about how it works: https://forum.stockmanagementlabs.com/t/multi-inventory-documentation
And I recommend you to try the demo site for free: https://stockmanagementlabs.com/addons/atum-multi-inventory/