First: check Telegram itself

Telegram keeps your chats in the cloud. If you only deleted the file from your phone (for example with a cleaner app), open the chat again and download the voice message once more.

Scan the phone

Open SoundRecovery and allow all files access.
Tap Start scan for audio. One stage checks WhatsApp and Telegram media.
In the results, search for "Telegram" or open the Telegram folders.
Listen to the files and restore the ones you need.

Files found in app caches are tagged App cache; they may have no name.

Protect future voice messages

Turn on Voice Guard and tick Telegram audio. It keeps a private copy of every new Telegram voice message and audio file.

A message that was deleted for everyone in Telegram is removed from its cloud too. Only a copy that was saved on your phone can be found.

Get SoundRecovery: Recover Audio & Call Recording on Google Play