For Trump the 400k presidential salary is measly. The dollar value lost by not working on his own ventures far exceeds a 400k salary, by orders of magnitude. His 400k salary donation is only a very small portion of his personal donations. If his donation of time to the presidency was properly valued it would most likely exceed all of his other donations combined.
Look for nasty Nan, and James Brown to try that angle on campaign violations, as a reason to Peach Fotee Fibe.