If there was the political will for it, nothing about our legal system makes it impossible to prohibit admitting confessions as evidence in court. We could just

If there was the political will for it, nothing about our legal system makes it impossible to prohibit admitting confessions as evidence in court. We could just say "those are never evidence, the prosecution isn't allowed to introduce them or even hint that they have occurred". Police could still use them as a lead, to track down real evidence. If the culprit claims to have disposed of the murder weapon and they discover the weapon where he said it was, that's real evidence. But more generally, eyewitness testimony itself (of which confessions are just a special variant of) should be inadmissible. Professionals giving professional testimony from notes and reports they have compiled should be the whole of it.