Hi f_louise
Thanks for going through those steps. If the issue is still occurring, back up your iPhone and restore it to factory settings using the steps in these links:
How to back up your iPhone, iPad, and iPod touch
Restore your iPhone, iPad, or iPod to factory settings
Set up your iPhone as new for testing purposes, record a new voice memo and see if you can share it as expected. If you can, restore your backup and try once more:
Restore your iPhone, iPad, or iPod touch from a backup
If you continue to have issues after that, reach out to Apple Support at the following link to look further into this with you:
Contact Apple Support
I hope this helps.