Recently Deleted only available for 1 day instead of 30

Re: Recently deleted messages only showing one day before permanent deletion

If you haven't already: You may want to check your settings to see what length of time is set:

Eg: Delete messages and attachments in Messages on iPhone - Apple Support

says:

"Automatically delete old messages

You can delete messages and attachments that are older than 30 days or a year old, on an ongoing basis.

1. Go to Settings  > Apps > Messages.
2. Scroll down, tap Keep Messages (below Message History), then choose an option.

Important: If you choose an option other than Forever, your conversations (including all attachments) are automatically removed after the specified time period elapses."

Also; you can check out how recently deleted messages are recovered below. You can see if this works for you:

Eg: Recover deleted messages in Messages on iPhone - Apple Support

says:

1. "Go to the Messages app on your iPhone.
2. In the Messages conversation list, do one of the following:

• • Tap Edit in the top-left corner, then tap Show Recently Deleted.
  • Tap Filters in the top-left corner, then tap Recently Deleted.

1. If you’re in a conversation, tap to return to the conversation list.
2. Select the conversations whose messages you want to restore, then tap Recover.
3. Tap Recover Messages."

All the best :-)