While it is easy to say all financial resources need to be dedicated to pitching, unless the Sox are talking to Bauer, there just isn't much out there. Paying Jake Odorizzi or Jose Quintana like an ace will not turn either into one. The Sox could (and IMO should) go heavy on bullpen spending and sign at least 2 from Robles, Bradley and Hand and shore up the very weak bullpen. But addressing the rotation with at least one starter is probably going to get something very mediocre unless the Sox go after Bauer. And the trade market has not seen any addition more compelling than Blake Snell or Sonny Gray, either of whom is likely to cost trade chips the Sox simply do not have.
Now the Sox could try to reduce the asking price from the Reds by including an underwater contract like Mike Moustakas or Nick Castellanos, but that doesn't mean Cincinnati will bite, especially if they view moving Gray as more than just a cost reduction. A similar strategy with the Rays is actually not very likely, especially since their only bad contract is Kiermaier, and he is very far from cancelling out the very high value of Snell and his contract.
Bloom turned the Rays into contenders by piecing together monster bullpens and watching his team implement strategies to maximize their usage. Granted, having Blake Snell pitch every fifth day certainly helped and is a luxury the Sox do not have now. But if you cannot build a great rotation, the next best thing is a great bullpen that shortens games to 5 or 6 innings for the opposition...