IMHO UK currently holds the gold standard for this https://design-system.service.gov.uk/ Most/many government services use the standard design architecture and, although it is not perfect, it is several orders of magnitude better than I've seen elsewhere.
Former CTO of a country here. Anything GDS did filled me with deep envy: it was beautiful and made so much sense and I had none of it at my disposal. Then Brexit. I was there in GDS offices a few weeks after the vote and the organization was being dismantled under my very eyes. See, the trick with such endeavors is not what you can drive centrally, it’s what you can make others implement. Reporting to the Man is a go…
My only success has been internal reviews of wcag compliance and the threat of fines if found lacking.
But for non digital design its embarrassingly hard