Shopify Variant Weight Display Fix

My Ella-based (Online Store 2.0) Shopify storefront already stores an accurate weight for every variant, but only the default variant’s figure appears. I need that weight to refresh instantly whenever a shopper:

• switches between variants
• changes the quantity in the mini-cart or cart page

The update must work across all products in the catalogue and surface in both the product page and the cart.

Please pull the weight directly from the variant object so the unit shown (kg, lbs or g) matches the data I enter in Shopify. No hard-coding; the solution has to remain theme-update friendly, so ideally a small section of Liquid/JSON plus a lightweight JavaScript snippet that listens for variant-change and cart-update events.

Once the logic is in place, test it on desktop and mobile with at least two products of different weights to confirm everything stays in sync.
Deliverable is the modified theme files and a short read-me so I can reapply the fix after future theme updates.