It seems that this statement can lead to different conclusions based on one's biases for or against Musk / freedom of speech:
1) The code base is a mess because the smaller, current team don't know what they're doing and/or management (i.e. Musk) is pushing them too hard and making poor decisions
2) The code base is a mess because the far greater number of engineers there before didn't know what they were doing and/or management weren't pushing them hard enough and were making poor decisions.
Both could be true but I'm going with something the more complex view that it's a little bit of everything, and that Twitter does seem to be moving in a positive direction overall.
The second being free speech, I'm a big supporter of that and there's certainly more of that now. It's not perfect but I'm not going to throw the baby out with the bathwater by arguing against perfection or pointing out some of the hypocrisies in play. It's a move in a positive direction.
They're comparisons against recent Twitter, which before Musk felt like an app with so many broken parts that were never going to get fixed (the login problem being the cherry on that cake for me). Now there's a feeling that things might get fixed, that new features definitely are coming, and that complaints might be listened to.
I also don't like the changes you've highlighted, though I do see them as inevitable at this point in internet history. We see Instagram and others moving towards paid verification, Reddit closing down its API and killing apps (and should we forget that Twitter has done this at least once before in one form or another). So, I don't think it's all rosy in the garden, but overall it's positive, and the negatives (mostly) feel inevitable.
Add to that, alternatives are now getting a bit of a look in from people that wouldn't have have bothered before. I don't think that Mastodon, to choose one example, is a direct replacement, but it's good that people are giving it a try.