Yet there could be sealed indictments that have yet to be unsealed. In fact, every single one of Mueller's indictments were originally sealed. Who's to say there aren't others that he's handed off to various federal prosecutors like at SDNY or EVDA? Assuming that Mueller has entirely cleared the president (or anyone around him) at this point is about as pointless as proving he's about to be arrested in the Oval Office.

Let it play out and see what happens. Regardless, I suspect Congress will inevitably get the truth out and eventually it will come out to the public. Like most things in a democracy, they're often slow and sometimes messy. This is a feature, not a bug!