They really dropped the ball, going for a single page application approach without emphasizing performance.
I mean I believe SPA's can be more performant and snappy than non-SPA's, but you have to have server-side rendering for the initial page load and minimize the amount of JS used. And then make sure rendering is fast; iirc they had inline styling everywhere a while ago (styled components?), and now nonsensical css classes (which, if they're unique, is probably good for css performance but probably still suboptimal).
They have also added a lot pop-ups, incredible amount of JS, suggestions to login (I use it mostly in incognito) and install their mobile app (if you use it on mobile). Such a mess.
Reddit's mobile site is also intentionally user-hostile to try to get them to use the app. Although that's not a part of the recent redesign, they had that for a long time now.
When they did the redesign, the first thing I did was Google on how to get the old interface back. That, and some custom CSS, means I get to see Reddit how I like it.
I mean I believe SPA's can be more performant and snappy than non-SPA's, but you have to have server-side rendering for the initial page load and minimize the amount of JS used. And then make sure rendering is fast; iirc they had inline styling everywhere a while ago (styled components?), and now nonsensical css classes (which, if they're unique, is probably good for css performance but probably still suboptimal).