1) That is unrelated to what I'm saying: less money = less chances of an anime. Nobody is saying that none else can chip in more money but... who would that be? It's the second season of a show, the audience is mostly fixed now. Anything can happen of course. That does not change my first statement: chances are low.

2) Name one single anime that switched themes between seasons and brought in so many new viewers. The manga is not identical to the anime. The anime boosted the "chill" vibes up to eleven. It's famous for that, just check any episode thread in the anime subreddit. But that simply can't fit well into a thriller based narrative arc. Before being a question about number of viewers, it's a question about if the director who boosted by his own volition the chill element wants to do a season where the chill element simply does not fit at all.

So not only there is the almost certain risk of losing most of your viewers, but there is also the doubt about whether the people behind it wants to do it or not.