Put me down as someone who quite enjoyed the humor of
How Much for Just the Planet? which definitely lives up (or down) to its title.
My example of a Star Trek book so bad it warped over to being an hilarious read would be
Black Fire by Sonni Cooper, where Spock ends up becoming the romantic pirate BLACK FIRE for part of the book (see
http://deepspacespines.com/2017/12/08/008-black-fire/ for a better review of this unbelievable book.
On a more serious note I've enjoyed most of the Original Series books noted in OP's post as well as the sequel to the
The Vulcan Academy Murders,
The IDIC Epidemic.