The functionality was identical between the two apps. The amount of tooling code and duplicative logic was massively higher because of SPA and all the fundamental things it demands.
Now if you really need an SPA for your requirements because you have an intrinsically complex front end and you've mastered the hoops to jump through good for you! There's nothing wrong with that. But there is something seriously wrong with building the same user interfaces we've needed for decades but the time code and complexity drastically increasing for no justifiable reason.