DAs of all kinds have enormous discretion. A significant part of our legal system is entrusted to them to act honorably, regardless of what judges and legislators say. DAs can't force outcomes that judges say are incorrect, but DAs can and do choose not to prosecute obvious crimes, and there are not great checks against that power beyond replacing them with the political process.

And even when cases are brought, the DoJ needs to defend them. See a number of cases that were very far along in the court system that the Biden administration was pursuing, that the Trump DoJ just quit defending. They simply no longer have a lawyer, and functionally cannot proceed.