Prosecutors are absolutely immune. Brady violations only invalidate the underlying case and in really egregious cases, ruin future careers in politics, but it doesn't create criminal liability going the other way. Police have qualified immunity, prosecutors have absolute immunity, as long as the charge is something that constitutes their quotidian work.

Private prosecutions do exist, but not on a federal level, and anything falling under the purview of the CFAA - which is the umbrella that hangs over all computer-access-related crimes, is federal by definition. Besides, with parallel construction, they can always legally reverse-engineer a legally sound rationale that doesn't violate the 4th Amendment or what-have-you. However, while prosecutors are absolutely immune, the police are not and therefore are subject, occasionally, to federal-level liability either criminal or civil, although the prevalence of police perjury - testilying, as commonly known - is both an academic niche that has produced plenty of papers and have achieved virtually nothing in the real world. The term came into the public consciousness in 1994 and as late as 2018 I've heard it bandied about by cops in a courthouse. Prosecutors need the cops to investigate (public defenders' have a much smaller team of investigators if you're lucky, but even then anything technical is hopefully something you know enough about to find the right expert and conduct a competent cross examination. The police, of course, have the first mover advantage and so they can set up the fall guy who is already pension-eligible and move their assets out of their name before getting tossed in the gentlest way possible under the minivan. I wasn't involved with the case but the classic WA case involving the police using all of their tools available to rearrange the narrative surrounding a murder caught on camera and a federal prosecution is the Otto Zehm case. I had the luck to see what happened at sentencing and it was frankly sickening. https://www.spokesman.com/topics/otto-zehm/

So, police do get prosecuted, but only below the federal level, and extremely leniently, and if weren't for the video it probably wouldn't have happened. Ten years for a murder caught on video is crazy considering that the feds were giving out pleas of 8 years for "trafficking" 4 pills of Oxycodone before fent got into the supply (also thanks to the feds, as it was entirely supply driven) and ten years after leaving WA I still have former clients incarcerated for much more ambiguous fact patterns and convicted after multiple mistrials. As for the feds, now that Bivens is basically dead, even their own IG reports read like lurid crime novels written in the most lawyerly way possible. And if they're really in trouble, creating a moral panic always works. It had worked so far.