Glad to see you back in the Community! I know how important it's to have a perfect tracking system for your inventory needs. QuickBooks Online has several powerful tools to help you stay on top of your day-to-day tasks. I'll be happy to share more on this.
When setting up an inventory item in QuickBooks Online, you have the option to assign a class and to choose a particular category for it. At the moment, there isn't any option available to assign a location. I can see how this would have benefited your business, and I invite you to submit feedback directly to our engineers. We are always adding new features to the program, and your opinion helps a lot with that.
Feel free to also to visit our Apps menu to explore any third-party app that could better assist you with your task.
You're always welcome to stop by if you need anything else! Have a great weekend.
Afaik, we will find this feature next year for QBO US version. It may take longer time available for other regions. A 3rd party app is a better option for the time being.