The UX for me went downhill the last 5-7 years. I don’t know if it’s react but something changed. Pages load slow or even don’t, strange display errors, slow reaction times etc.

Too few run output analysis on their bundles or even track bundle sizes. There's a lot of kitchen sink repos, not to mention any number of other bottlenecks between the front end and back end. Worse across split teams for larger apps.