But the jury only heard the evidence the judge allowed - most of the appeal was around the defence's assertions that the original judge had erred in allowing the jury to hear the bulk of the evidence (Evans' testimony, air embolism stuff, etc). So while yes, the jury made the ultimate decision that she was guilty, the information they used to make that decision was based on what the judge decided was admissible.
The experts speaking up now are experts in their fields, but not experts in the law. If they haven't even looked into the actual details of why she was convicted or why expert testimony was rejected on appeal, etc, it's not particularly helpful to Letby's case as it's too vague and abstract to be useful.
I think it also leads to shallow media interviews and to the interviewers and interviewees speaking at cross-purposes, as only one knows the details of the actual court case and only the other knows the details of their specialist field, so neither can bridge the gap in any meaningful way for the audience to come away better informed.
What I think would be far more helpful to Letby would be experts speaking up who have familiarised themselves with the detail from the case that's relevant to their area of expertise and the point they are making, so that they can point to specific places where the judges have erred.