You really need to get the bass right, it's at least off with a semitone, and some times more. Play the bass at the same octave as the electric piano. Now play them together, now copy the ground note from the chord, often the lowest note. If the chord is an E minor, then you should copy the E from it, and paste it into the bassline. Is the lowest note a G, then lower the highest note with one octave, Is the lowest note a B then raise it with one octave. This way you'll always get the right notes to prevent the music sounding low grade quality.
Please don't get me wrong, you've got some severe ill potential with this beat man! But you need to fix the bassline. I'm using almost always exclusively VST plugins to write down my chords right from the very get go, since it is often pretty hard to get the music right from just using samples. Unless ofc you got a good hearing. That's why I pretty much never sample from anyone else but my own productions.
Got access to a piano? Lay down the chords there first, and jot down the chord sequence through notes. Even a tiny 2 octave MIDI keyboard works wonders. I record all my chord progressions step by step into FL Studio to get the dynamics just right.