I guess I won’t be holding my breath in hopes that a single solitary thing will come of this.
You are correct. You can’t convict a King.
Trying the case in the court of public opinion ought to do enough damage by itself even if it doesn’t get to the impeachment stage.
And remember there are a lot of Republican House members who hate this guy enough to use a genuine legal opportunity to take him down through impeachment. If he DID break the law, and the above material suggests that he did, any attempt by the Ds to defend him would become their Verdun.