When you can’t restore your previous text messages from iCloud backup, what do you do to retrieve them?

Note that if you’re using messages in iCloud (Set up iCloud for Messages on all your devices - Apple Support) then messages are not part of your iCloud backup file.

When using messages in iCloud, deletions are instantaneous, sync’d across all devices, and permanent.

YhWhRED wrote:

I couldn’t restore my deleted messages with iCloud backup, how do I restore deleted text messages when iCloud backup doesn’t work?

That is the only way to recover message.