I keep seeing projects that could have been written as a traditional multi-page application pick an SPA architecture instead, with the result that they take 2-5 times longer to build and produce an end-result that's far slower to load and much more prone to bugs.
Inevitably none of these projects end up taking advantage of the supposed benefits of SPAs: there are no snazzy animations between states, and the "interactivity" mainly consists of form submissions that don't trigger a full page - which could have been done for a fraction of the cost (in development time and performance) using a 2009-era jQuery plugin!
And most of them don't spend the time to implement HTML5 history properly, so they break the URLs - which means you can't bookmark or deep link into them and they break the back/forward buttons.
I started out thinking "surely there are benefits to this approach that I've not understood yet - there's no way the entire industry would swing in this direction if it didn't have good reasons to do so".
I've run out of patience now. Not only do we not seem to be learning from our mistakes, but we've now trained up an entire new generation of web developers who don't even know HOW to build interactive web products without going the SPA route!
My recommendation remains the same: default to not writing an SPA, unless your project has specific, well understood requirements (e.g. you're building Figma) that make the SPA route a better fit.
Don't default to building an SPA.