I think the view transitions API will be good, but it's currently only available for Chromium browsers so it is not really a competitor to SPAs for the time bei

I think the view transitions API will be good, but it's currently only available for Chromium browsers so it is not really a competitor to SPAs for the time being. I'm also kind of opposed to really broad generalizations like this since what is most effective currently kind of depends on what you're building. A calculator built as an MPA would be kind of ridiculous.