@Jeremy3292 Having used the MXM4 once on my Model S, I can assure you it must be suspension that you find harsh, not those tires.
Not saying they're anything special for ride quality but they were at least mushier and softer feeling than the performance tires I've typically used.
Model S air suspension rides quite well and the MXM4 didn't change that.
Personally I hated the MXM4 for its low grip, mushy cornering, and poor road feel...but ride quality, noise level, and efficiently were good!
Btw when was your Model 3 built? I found the stock ride quality of October 2021 Model 3's to be fine -
not great, but decent, just a little busy and bouncy ride but not nearly so bad as a Model Y of the same era. However there's many reports here that older Model 3 had firmer suspension tuning, with worse ride quality, though possibly better handling.
(I've since upgraded my suspension and my car now rides and handles better than stock, at the same time, when set on the medium to softer end of my adjustable dampers. But aftermarket suspension is not for everyone...it would be nice if Tesla offered higher quality damping from the factory. I also went for firmer springs so when driving slowly on certain surfaces they'll make themselves known no matter how gentle the damping is, but stock-like spring rates were an option, I was just more focused on handling upgrade than ride quality.)