The first three bullet points could have easily been done before even starting the process. The trade deal could have been negotiated in the two three years before leaving. The fourth one is a really weird move that will still become a nightmare to figure out in detail - something that didn't happen either.

Not the negotiations took time, no. The UK needed four years to figure out what it wants to negotiate about. Figuring out all the details of what that means is still open, and that's why the UK needed yet another extension, or something that is effectively the same (just without voting power in the EU now). And I'm quite certain it will extend this extension again.