You are 100% correct that it’s ridiculously low for the severity of the crime he committed. It should be 20+ years.

But based on what I’m seeing other Jan 6 seditionist get (and keep in mind this is all somewhat based off of federal sentencing guidelines and DOJ recommendations by the line prosecutors in these cases) my guess is he gets 4-7 years if he takes a plea deal and 5-8 if he goes to trial.