Right, so there's probably a discussion that needs to be had with your enterprise architecture team on why said stack was used (irrespective of skill sets available) when certain features are available "for free" (e.g. the DesignSystem)

I'll have a wild stab in the dark in saying that if the stack is really tightly coupled, that there's extra labour required by the dev team to meet the Digital Service Standard. Which is, really speaking, unnecessary public expenditure.