At the same time, I'm not sure if taking 2 months to get productive is a win? Wasn't one of the angular "upgrades" a total rewrite? What is the overhead of maintaining a second tightly coupled front-end app. I found doubling the surface area seemed to square the effort, not double it. How much of that productivity is illusory and could be done with fewer people?
Some folks are upvoting the heck out of my comment. I presume some portion of those are devs who might like working in a place without JS dependency package/upgrade/language/promise hell?