Hello,
As you know, for Variable Products by default it shows the Price Range. On your Site, for the Variable Product like the one you mentioned by default, there isn’t any Variant selected as default which is why you aren’t able to see the Discounted Price when opening the Product.
So, there are two ways as an alternative in this regard which you can try out.
One is you edit your Product > there go to Product Data area > in that go to Variations created > there you can find the Default Form Values > there you can select any of the Variants created having Discounted Price > so when you visit your Product, you will get to see the Sale Price of your respective Product: https://ibb.co/jrjL2sP
Or you can use the Theme’s new feature of Show Single Variation which can be found under the Dashboard > Theme Settings > Shop > Variable Products > Variation as product > Show single variation: https://ibb.co/r2Smyt0
In this way, all your Variants will be shown as individual Products with respective Sale Prices.
Best Regards