Configurable products with unique URLs

At present we have all our products as simple products, but some of these are similar with different sizes etc, so should really be set up as a configurable product. We want to change these so, all skus still show in the product category, but navigating into one of those pages includes the different options. When clicking a different option, it reloads the page with the unique URL from that sku. Example https://www.ikea.com/gb/en/p/malm-chest-of-3-drawers-grey-stained-10482512/ has easy options that use a unique URL. Amazon also do it like this. In magento it seems you need to create a new sku for a configurable product, and it doesn’t seem like you can select existing skus.

https://www.axminstertools.com/nitrotouch-glove-size-8-m-953639 is a M2 website, that is fast loading when changing the product options with unique URLs.