Regarding the delay of the 2024 Watchtower, I tend to agree with others who have posted that the JW leadership is waiting for the outcome of a serious legal issue. The Watchtower has become dependent on Government subsidies and tax exemptions that they will make doctrinal and organizational changes, no matter how radical, in order to keep these monetary benefits.
Though it is speculation on my part, we can expect significant changes in the JW religion as the Watchtower leaders try to implement Governmental demands in order to keep their charitable status.
As to Kingdom Hall attendance, I think this is a local issue. As some have posted, attendance is down. While others have noted that attendance is up. Since it has been almost 40 years since I attended a KH in my area, I have no idea whether attendance is up or down. But I have noticed that while a few local JWs do cart work, I haven't seen JWs engaged in d-d witnessing in our neighborhood in almost 20 years.