The obvious upshot of today's decision is that the three pending criminal cases against Donald Trump will not go to trial this year. (And maybe not for a while after that.)
That said, based on some of the back-and-forth at arguments, I'd be a little surprised if DOJ hadn't already gamed out what a purely-unofficial-conduct indictment might look like.
It is unclear, messy, and time consuming by design. It is a massive hurdle for any prosecutor or court. It pretends there is not complete immunity, but it makes it practically impossible to actually act in a timely, meaningful way.
Can any cases now go forward against the Congressional insurrectionists?
As I recall, the explanation last year was that Jack Smith was focused on nailing Trump and Congressional indictments would muddy the waters, which are now thoroughly muddy anyway.
Republican Justices helping Trump to escape justice. All Republicans do is lie, hence when they say they are the "Tough on crime, law and order party", they are full of crap. Republican Justices will happily execute an innocent Black person.