If I had owned this place from the start, I'd have asked the question of "what business outcomes …

One of the mantras I like to chant is that your job as a developer is not to write code. Your job is to implement solutions to business problems. I didn’t understand that until I became a manager. Your whole perspective shifts because you realize that salaries don’t just grow on trees.

One thing to consider: a lot of devs are most familiar with React and some set of tools in it's ecosystem. Sticking with what you know is generally good advice. Especially if you consider hiring and onboarding.

> the people involved were excited to further their careers on this, so motivation to call out unneeded complexity was low. I strongly disagree. The fact of the matter is frontend tech debt is just SO MUCH cheaper than backend tech debt. If all you need to do to is refactor or port over a SPA and leave the existing API alone, you've sidestepped so much pain it's unreal. If you started out with "simple" form requests instead of an API, the backend is pretty much guaranteed to be an undisciplined mess. Wrong place to cut corners.