For me personally the most infuriating example of this is the Azure Updates[1] page, which in my job I need to check nearly daily to see what's reaching EoL, what's new, etc...

A couple of years ago they redeveloped it as a SPA app.

The original server-rendered version of it worked just fine, but it "had" to be made into an interactive client-side monstrosity that loads many times slower for "reasons".

It doesn't even load successfully about a quarter of the time. It shows items in reverse order (entries from 2013 first), which is some sort of async loading bug. They will never fix this. It's been there for two years already, it'll be there for a decade more, mark my words.

Then, it takes about a minute to load sometimes on a poor connection.

The links are JavaScript and don't allow "open in new tab".

Etc...

All of this to enable client-side filtering, which is a non-feature nobody ever wanted. A simple server-side filter capability would do the same thing, faster.

And anyway, the filtering is broken! If click the "New or updated" filter, it drops down an empty selection with no options. Clicking anything else doesn't change what is shown!

While developing this over-engineered monstrosity, they took the original site offline for "maintenance!"

Hilariously, despite Azure having multiple CDN products, the Azure Updates page doesn't correctly use their own CDN and marks almost everything as "no-cache; no-store" causing 2.5 MB (after compression) to be re-transferred every time, despite using unique signed URLs with SHA256 hashes in them!

This is the state of web-dev in the 2020s: A multi-trillion-dollar software company can't hire developers that know anything else other than SPA web app development!

This commonly used page has spectacularly poor web engineering, and this is from a company that sells a web app platform, a CDN, and the ASP.NET web app development framework!

If they can't get it right, who can!?

[1] https://azure.microsoft.com/en-au/updates/