Brain Fart - Simplest way to update many records in another form with my current form?

Brain Fart - Simplest way to update many records in another form with my current form?

I feel like I should know how to do this, but my brain mapping of how to solve this just isn't working, or maybe I'm overthinking it, or probably both.

So I have a form for my products, called "Add_Product".  This is where data is stored about each product, like its name, size, quantity on hand, etc.

Then I have another form for quick inventory updating called "Add_Inventory".  In this form, I have a field for each product (I know this probably isn't the best way to do this, but it seems to work best when it comes to using the Zoho Creator mobile app, but other suggestions are warmly welcomed!).

On submission of my "Add_Inventory" form, I want to update each product's "Quantity_On_Hand" field in "Add_Product" where the field names match (again, suggestions welcomed).

I know that I could write a bunch of if statements and fetch each record individually and then update it, but there must be a simpler way to do this using a loop, I just can't figure it out...  Any ideas/suggestions/recommendations/solutions?

Thanks guys and gals--Any help is greatly appreciated!!