Legitimate way to recover deleted voicemail?

I am wondering if there is any legitimate way to recover a deleted voicemail that is not in my deleted messages? It is a final voicemail from someone who passed away and I've accepted it may not be possible to get back, but want to try whatever I can.

I already tried wiping my phone and restoring a back-up, but the back-ups were from after it was deleted. I've also researched data recovery apps, but I'm unclear if any of them actually work.

Thanks in advance for any help!