I'm at a place where we've acquired a company that does something similar but through PHP/jQuery, and it's been a herculean effort to make any changes or improv

I'm at a place where we've acquired a company that does something similar but through PHP/jQuery, and it's been a herculean effort to make any changes or improvements as there were no abstractions at hand. After many failed attempts at a re-tool/re-build, we've settled on showing a blank page that we then hijack to show a React page that's build on top. New FE devs that come in now have a 6 month period where they must learn a new proprietary tech just so that we can circumvent what's already there, I would say that it's not a great idea if you have to work with other FE devs (who are not Full-stack) and if your app is of a significant size (YMMV I guess, we've had our own issues with GraphQL too).