Update Qty selector on Shopify

Looking to customize the Qty adjuster on Shopify Product Page. I sell batteries and their wholesale packs are in 10s and 5s. So I need by Qty selector to show a dropdown in multiples of 10s and 5s. For instance - on 1 product the qty selector should be 10,20,30,40,50.....,100, and so on. Attaching ss below. Also would need to be configured via TAGS so I can add it on any product that I want. And, if possible I'd also like the discounts to be given according to the qty selected.