Try this (I’m using the Arturia Mini V)
1. Oscillators: Two osc, both medium Pulse waves. Detune one up 30 cents, the other down 30 cents. This will give you that real aggressively out-of-tune tone
2. Enable the “Out” switch and External Input Volume to about 8. This will overload the filter and give us some nasty distortion, introducing the lo-fi aspect.
3. Increase Filter Emphasis (Resononace) to about 3.5 to get extra buzz on the top end, again giving us a more lo-fi feel
4. Set you pitch bend rage to 2 semitones, and then manually bend pitch when needed