I doubt a club will just pump a one time windfall into transfers. That sounds a bit reckless. I'd guess they will rather use it to handle their debt and build their new stadium (that's still an ambition, right?) without bleeding out on the sporting side.
The stadium is supposed to be a separate investment.
So far one Berlin newspaper claims they'll invest 80% into transfers, which sounds a bit extreme even if it's spread out over a few years. Another one claims they'll go for debt reduction first which is what they did when KKR was still around.