Valve seems to have improved the rate limits when checking inventories. It's not quite what it used to be prior to October 2022, but it's certainly better than what we had until now. I have gone ahead and optimized the back-end and reverted the changes that were made in 2022.

• The site will once again check inventories of Steam users outside of the Inventory.gift community for gifts.
  
• Owners of popular gifts will have their inventories checked periodically for a more up-to-date database.
  
• Your own inventory will be updated once every 24 hours (instead of 48).

Have fun trading!