Ouch. That torture includes …
Pitch-shifted up by ~25%
Sharp high-pass @ ~200Hz (so like a phone)
Painful resonance @ ~4500Hz (probably not a deliberate effect)
Chorus*-type pseudo-stereo.
Dynamic-range-compression.
Reverb.
[ * possibly double-tracking too, where the same vocal is recorded twice ]
It’s as if they literally ‘phoned that in’, from a bathroom.
If you want lo-fi nastiness there is an Audacity plugin for that: HelmetRadio1-5.