IMO the real failure here was not having an internal administration website with all the auth and API plumbing already set up, which you could tack a new page o

IMO the real failure here was not having an internal administration website with all the auth and API plumbing already set up, which you could tack a new page onto with minimal fuss, and a backend to tack a new API endpoint onto with no hassle. If you're building a new internal webapp from scratch for a small internal use-case, you just end up with a hundred different poorly-maintained apps. But in the situation where you're adding a page to an internal app, it's trivial to make that new page a SPA React app, since the framework is already there waiting for a new component.