While I’m a big fan, I think this blanket statement won’t actually solve OP’s problem. The 2m blue is known as a very bright cart, and has been reviewed as fatiguing to some (myself included)
While it’s true the Rotel might be amplifying the problem produced by the cart (no pun intended), a 2m blue paired with a marantz might still be too bright for OP’s preference. I’d personally start with a new cartridge as it’ll be the easiest part of the system to invest in and would most likely solve the problem.