A Reel has room for a few sentences, not a speech. Write the line you would say to a friend, hear a sample, and make that one voiceover.
Keep the script inside one voiceover
Aim for well under 2,000 characters. If the line is long, cut a sentence before you pay for it. The studio shows the character count before you make the voice.
Use the same voice next time
People recognise a series by the voice as much as by the picture. Pick one sample and stay with it for the next Reels. Download each mp3. The file on the account lasts seven days.
You can crop a quiet start or a long ending after the voice exists. That edit does not spend characters.