He may have gotten outfoxed then. If anything, I wouldn't put it past Pelosi to be tough in negotiations to see if she could wear him down and then blame him for backing out of the negotiations. I think she may be better at "the art of the deal" than he is. Trump is used to using lawsuits and the threat of lawsuits when he makes or breaks deals. He's used to dealing with people poorer than he is who can't afford lawsuits; and he's used to taking on one person at a time. He's not shown me he's very good at multi-lateral negotiations or at political ones. It was weird to me that McConnell wasn't involved in the negotiations. Why was it Pelosi and Mnuchin? I'm thinking maybe McConnell gave up a while ago and decided to push through anything the President wanted. He blustered that there wouldn't be a deal without immunity from lawsuits for employers if employees got Covid. That didn't go anywhere; and the next I know, it's Pelosi and Mnuchin?I seriously doubt that he was thinking about much else than getting revenge against the Democrats. And if there's a backlash of any kind due to his decision, then he'll turn it around and blame the Democrats. He won't take personal responsibility for the outcome or the potential fallout.
You're right -- he'll blame the Democrats -- but will that work for him? I doubt it. A saner approach would be to have allowed the House and Senate thrash things out -- and then sign whatever they agreed to. A President often can get what he asks for by telling Congress what a bill must have and must not have for him to sign it.