I find loading a MC can change how bright it sounds.
I ran through the calculations years ago and found that it isn't actually possible to load a MC cartridge properly. You can have them loaded badly, or you can have them loaded worse.
A Grado moving iron cartridge with Frank's Longhorn mod running into a 10Kohm load does a pretty darn good job. I don't see much improvement being possible. You start to run into the limits of the phonograph system itself.
I have a very good local orchestra (it's one of the Big Five), so I can refresh my hearing with live acoustic music. We also have a top notch music school nearby, so I attend concerts there too.
I listen to other types of music too, but I think that I have a pretty good idea of what live acoustic performances sound like.
I don't find that MC cartridges sound much like live music. Some MM or MI cartridges sound more like live music. (A good CD is even closer.)