A whole stack rewrite is not always (in fact very rarely) a good idea. The backend often drives a lot of logic; in a big rewrite, the less you rewrite the more likely you are to be successful.

Too many big refactors fail because they aren’t done in value-adding steps.

Also your second paragraph isn’t in line with your first … in react you don’t write “hundreds of lines of js” for a table. You write the html as js (jsx), and sprinkle the dynamic parts on top. It’s equivalent…