If you want to keep track of inventory and prevent overselling, then yes you'll have to enable inventory tracking.
You can show anything you want on the website. For example, if your site is currently showing the inventory quantity on the product page, look in your theme code to see where that's being shown, then remove it (do this on a duplicate theme so you can test first. For working with themes, here are some tips: https://speedboostr.com/how-to-safely-edit-your-shopify-theme/).
For product page, start with the product.liquid Template, then read the code and include statements to trace through the file until you find the code for quantity.