Aftermarket head unit sound quality

Hello everyone, this is my first post on this website so i'm still trying to figure out how it all works. But I have recently installed a Sony Carplay head unit in my 2008 Sequoia Limited with the JBL upgraded audio system. But when I play music through it the Bass is horrible it's sounds awful like it's hitting ranges that it's not supposed to and is trying to send bass through my smaller speakers in my front dash and it distorts them. My car has a factory sub and I put in new front Midrange speakers in the doors and new front dash speakers. On the OEM head unit it sounds amazing the bass is crisp and the overall sound quality is really good but with the aftermarket head unit it doesn't sound good at all. I've messed with the Equalizer settings and the Crossover settings. If anyone can tell me what I could do to help I would appreciate it.

 

If you are really serious about good sounding stereos, just rip out all the jbl stuff and put a 5ch amp in, a few sets of components (could probably get away with just reusing the jbl door speakers) and a sub in a proper box. You'll always be hunting something down thats fighting you.

 

Is there anyway I can just replace the amp and keep the rest of the speakers and other stuff? Cause my speakers are in good shape and sound good and the sub is pretty good stock but i was looking for a different sub.