https://alexkrupp.typepad.com/sensemaking/2022/06/angular-wi...
If you look at the distribution of PageSpeed Insights performance scores, it's very clear that choice of framework is not what causes bad performance. The data shows that Angular might be a little better than Next.js for getting top scores, but for the vast majority of sites, the reasons for bad performance have nothing to do with framework.
Put another way, the average Next.js site has a performance score of ~35, which is terrible. If you were to rewrite your site in Svelte, then maybe it would go to 36, which is still terrible. Unless you are already spending the money to be in the top 1% of all websites in terms of performance, then you might as well just pick a tech stack at random -- at least as far as performance is concerned, obviously there are other factors at play.
To make this even more concrete, let's say it would take 18 months to rewrite your front end in Svelte -- so ~3,000 hours to get an expected PageSpeed Insights improvement of 1 point. Alternatively, let's say it takes 5 hours to replace Moment.js with Day.js, which has an expected improvement of 5 points. That means replacing Moment.js with Day.js would be, on an hour-per-hour basis, 3,000x more cost effective than switching frameworks. And yet nearly every time I talk with a startup that is considering doing something about their slow SPA, it's usually just spending millions of dollars to rewrite it in some trendier framework.