I own an old Marantz like that. It was my Dads but I am not sure the model at the moment. Anyway old Marantz is super warm and I used it on some bright B&Ws with good results.
I am a musical fidelity fan and have heard them sound great on a pair of wilson Sophia 3… tons of bass slam. But in your situation I personally would sell it. While good no point in buying colored speakes to work around a sound you don’t like.
Anyway nothing new is as warm as old Marantz really. I think some McIntosh amps are similar to Marantz’s house sound ( I own both McIntosh and Marantz). Maybe something like the MA352 would do the trick as it is a touch warm or older Mac amps. The newer ones from the current line are more neutral.