One thing I have noticed in prior versions of this game, that continues in 2021, is the way that the star ratings are heavily influenced by certain player attributes, while ignoring others to the point where they become a poor representation of player quality.
The essential issue is this: star ratings are heavily influenced by a player's "scoring" rating, while the "defense" rating has little effect.
The thing is, a high scoring rating is sometimes not even a positive attribute. There is no question that the worst players in DDSPB are those with a high scoring rating, but low FG%. These guys will just kill your team, going 10/30 every night. Pair that with a poor defense rating and you have a guy who might have 4 or 5 stars, cost $30 million a year, and doom your team.
On the other hand, a player with a high defense rating and a low scoring rating is always helpful, even when they are not good shooters (because they won't kill you by shooting too much).
Complicating this a bit is the fact that the FGI and FGJ ratings do not necessarily translate into decent FG%. I have seen guys with a FGJ of 5 consistently shoot well from deep, while others with an 8 or 9 shoot 25%. The best way to tell who can hit shots is to look at their stats over their ratings (which is a bit more difficult for young players).
As an experiment, I took the Sacramento Kings and edited the entire roster. I kept all ratings and traits the same, but for 2: I turned everyone's scoring rating down to 20, and everyone's defense rating up to 100. Shooting, stealing, etc. all remained whatever they were originally.
Most of the team wound up with 1 star overall ratings; some had 1.5. DeAaron Fox was the only player with 2 stars, likely because of his great passing/handling skills. According to the star ratings, this was the worst team in NBA history. Utterly doomed, and not likely to compete in even the G-league.
In 51 games with this modified roster, they went 26-25. They were the lowest scoring team in the league, but also allowed the fewest points. They were not a good shooting team(but the Kings are not a great shooting team anyway), but the biggest problem with the lack of scorers was the team would take forever to get a shot up. There was no pushing the pace because no one wanted to score, but they were still decent, about as good as an unedited Kings team would have been.
I then re-edited the roster. I turned everyone's scoring up to 100, and their defense down to 20. The lowest star rating was now 3 stars. Fox and Holmes were 5 star players. No team came close to such star quality - they appeared to be the class of the league. They went 9-22 the rest of the season and missed the playoffs.
Scoring went up, points allowed exploded. The team FG% didn't improve at all, but they took a lot more shots. Meanwhile, they could no longer stop anyone and just got whipped most nights.
Obviously, there are issues with this experiment - there are diminishing returns to having great scorers - there is only one ball, and a 5th option who has a scoring rating of 100 isn't really doing anything for you. OTOH, every strong defender provides roughly equal additional value - having 5 on the floor at all times means there is never an easy matchup to exploit. Also, the Kings are not a great shooting team, which hurts them in every case, but hurts more when they are maximizing the number of possessions by shooting a lot.
Still, the fact is a guy with a great defense rating who hits his shots is a valuable player even if his scoring rating is low, but such players almost never get more than 2 stars and are often available for league minimum. Meanwhile, a player who shoots poorly but has a high scoring rating is a team killer (especially with a low defensive rating), and they demand high salaries to lose games for you. Focusing on collecting strong defenders with solid FG% creates a huge opportunity for arbitrage, and once you now this it is unfortunately far too easy to build a team that consistently wins ~70 games a year.