My favorite is when they call and instead of the call going to voicemail, it goes to a voice assistant screening service because it's an unrecognized number, and then they proceed to blurt out a bunch of shit because they think it's voicemail. Meanwhile, all you get is a shitty transcription that gets nuked after you read it. Bonus points if it's full of tech jargon that the transcription service can't parse.
My second favorite is when my voice mail inbox is "full" because apparently my cell provider won't let me have more than 10 messages in there at a time, in spite of nearly all of them being car warranty or student loan scams that I just haven't deleted yet. It's fucking bullshit that blocked/reported numbers can still leave voicemails on some carriers.
On the death/thrash front, have you stumbled across Crypta and/or Nervosa yet? Same label, and a couple of the same members; Crypta is an 80's/90's death metal throwback with more modern production techniques, and Nervosa is more thrash-oriented.