If you want to display several decimals when displaying the quantity on your product you can follow the method below.
Step 1 : Check your product quantity at Products or Product Variant
Step 2 : Menu Setup - More Menu - Module Configuration - Inventory - Display
Note : In this case i changed to 4 so I get longer decimal behind the comma.
Step 3. Check the result on product menu or inventory
Then the results that will be obtained are as shown below. You should see the differences between 2 and 4. 2 mean you wanted to get last 2 number from decimal and 4 mean you want to get 4 number from decimal if you do not wanted to show the decimal simply change it to 0.