Whatsapp message recovery from old phone or icloud backup of phone

[u/Antique-Swim-4008]

After receiving a new Iphone, the old one’s screen is black but the phone appears somewhat functional, I accidently backed up the new phones messaged over the old save, erasing my years worth of message history. Whatsapp claims that it only ever hold one backup at a time for a given account, as unbelievably stupid as that seems, is there anyway I can retrieve my old messages. I have the old phone but given that I already back upd the message son my new phone I assume if I fixed the pohone andn booted up whatsapp it would ask me to resign in with the new messages, I do have an icloud backup of this entire phones data from before this whole incient, could this be uses to retrieve my message data?

Thankyou, there is sentimental messages on this phone