It is not possible to change the order of specification values for accounts with a large volume of values. When the order of some value is changed, the page reloads and the change is not saved

1. From the side menu, click Catalog.
2. Click Categories.
3. Click a category that has registered product fields that were not inherited from another category.
4. Access Actions > Field (Product) or Field (SKU).
5. Click Values and change the order of values by the sort icon
6. Note that the change was not saved

Within Admin, there is no workaround

In the storefront, you can apply customizations to change the order