Apart from using the aforementioned methods, you can recover the deleted voice recordings from iCloud web. But it only works when you have saved them to iCloud Drive.
Step 1. Use the same Apple ID to log in to iCloud.com and click iCloud Drive.
Step 2. Open the file where your deleted voice recording is located.
Step 3. Double click on the voice memo you want to recover to get it downloaded.
If you are wondering about how to recover deleted voice memos on Mac, try AnyRecover - a top data recovery helper for Mac.