Hello george2709robinson,
Welcome to Apple Support Communities!
We want to help so you're able to access and play these older voice memos on your iPhone again.
One of the first steps to take is to check for any pending iOS updates, which can help make sure the software is working as expected:
"Update your iPhone or iPad wirelessly
- Back up your device using iCloud or your computer.
- Plug your device into power and connect to the internet with Wi-Fi.
- Go to Settings > General, then tap Software Update.
- If you see more than one software update option available, choose the one that you want to install.
- Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do."
This Apple Support page can help get those updates installed: Update your iPhone, iPad, or iPod touch - Apple Support
Then try again to play:
"Play a recording in Voice Memos on iPhone
In the Voice Memos app
, tap a recording and use the playback controls to listen to it.

Control
Description

Play"
Detailed here: Play a recording in Voice Memos on iPhone - Apple Support
We hope this helps to get the memos playing normally again.
Cheers!