There's no proof Trump has asserted executive privilege, so there might be nothing to protect Navarro and others from the reach of the Jan 6. committee. If this subpoena actually exists, Navarro is going public because he's getting worried he'll be compelled to testify before the committee - and more truth about that fateful day will be uncovered.
Unlike the Democrats, the majority of Americans have moved on from talking about Jan. 6. The Dems are desperate to not lose control of the House in Nov. - but not even their political witch hunt will stop Trumpism, make Biden less of a failure, or prevent a Republican takeover in the midterms.
There's a 50% chance that 15 or more people will be charged by the US DOJ with seditious conspiracy in connection with the Jan 6th Capital riots, according to the Metaculus prediction community.