I have messages kept forever in icloud messages - approx 3,700 messages, however, there is no way I can find either via PC or phone on how to view them?

Iphone 16, upgraded from a 14 which I still have, shows nearly 4K messages in storage but, there is no way to retrieve them via desktop or phone that I can find?

Please help as some are urgently needed for a legal case.

It's doing my head in trying to find out how to access them and download them to either the phone or the PC?

Messages are kept forever.