Hey there, @MaxRSG !
Bo here from Shopify Support!
That is a really great question. This feature can be added to your theme with the simple use of an app. The app I would recommend in this case is QuickView by Secomapp. This extension gives your shoppers quick access to product preview in one click without reloading the whole site. The Quick view (Quick Shop) app will not only reduce the shopping time but also bring a convenient experience to shoppers. Your shoppers can view product details quickly without leaving the catalog navigation. This makes browsing products easier and faster, which encourages sales. Products may be added to their cart from the Product Quick View page.
Another option here would be MultiBuy Add to Cart Booster. This app will allow your customer to choose the variant and quantity they want but does not show a brief description.
There may also be a coding solution for this that falls outside the realms of what the Shopify support team can provide. If a developer/expert does not respond here with advice on how to achieve this through coding I would recommend reaching out to a Shopify Expert here, or at HeyCarson or TaskHusky.
All the Best,