I seriously doubt that. Catalans got everything they wanted: amnesty for the thieves and more money in the budget. They were basically setting the agenda for the government over the last couple of years. Their base can see this and will not abandon them now. It's still not clear if Pigdaemon will be back before the elections but if he is then he will be welcomed as a great hero and will serve as the face of Catalan victory over the rest of Spain. This will give them even more votes.

If you're thinking they may lose support because they blocked the housing decrees... definitely not. It was clear from the beginning that landlords form their base and they are grateful that Junts blocked the new law. That's why I think Sanchez sabotaged those changes. It would be easy to negotiate a solution that Junts would approve (exclude small landlords from eviction bans) and for some reason he pushed for changes everyone knew will go nowhere. I think his calculation is that he can present PSEO as the only chance to get housing reform but I also think people will not fall for this.

My instance doesn't have downvotes but I'm guessing people don't want to admit that Spanish government is not perfect and they think that only a fascist would dare to say something like that.