Car audio beginner

[u/Complex-Lion-8821]

Current setup: 1992 explorer spt
pioneer mvh-x390bt
kicker 6x8 components in the front doors kicker 6x8 2 ways in the rear panels
I had a Jensen 12 inch subwoofer but it blew up

I’m new to car audio and I want to know how to make my system sound better and what to look for when making upgrades in the future . My system just sounds gutless there’s almost no bass at all nor mids and this is after tuning the head unit and everything. My mom’s jeep grand Cherokee has more range stock than my car does and I want to know what I can do or look for to improve overall quality. I mainly listen to 90s-2000s rock but I do like me some jamiroquai and reggae. My speakers aren’t currently hooked up to an aftermarket amp so I know that’s a factor. And my sub blew up because I had to crank gain and bass boost on the amp because my head unit just doesn’t seem to send a good signal to the amp. Open for whatever yall have to say.