If Moshiri was the real deal he would see Chelsea's £50 million valuation of Costa and throw it on the table/ cash + Barkley and throw £200-250k a week on the table to a top player who let's be honest seems to chase the money.
That's what you need to do when you don't have CL football, that's what City, Chelsea, PSG and all the other clubs done but we won't do it as he isn't the real deal in terms of an owner willing to throw silly money around to build a genuine CL quality side.
Problem is to sign a proven goalscorer in the current market like Benteke for example will cost you around £40-50 million and £130k a week anyway, so Go all out and try get a statement signing who'll get you 20 goals a season.