Successful design systems move more slowly than the products they support. That’s a feature, not a bug. The slower pace doesn’t mean that design systems have to be a bottleneck to shipping product.
Product can’t be expected to pause for the design system to catch up. If they need a feature that the design system does not yet (or may never) provide, the product team should move ahead and build the solution themselves.
The job of the design system team is not to innovate, but to curate.