Posteo doesn’t have to retain IPs and doesn’t, it also doesn’t retain payment info (though if you transfer by wire there’s still a window where a payment can be traced AFAIU).

They will also absolutely forward any and all traffic for a particular account to law enforcement when given a court order. What’s it with criminals thinking that they can outsource opsec to legitimate businesses. Defending against a state-level actor actively hunting you down, watching closely and pouncing on any and every mistake, is a vastly different beast than making sure google doesn’t know about the butt plug you just bought.