I haven't heard of anything that 'fixes' pre-recorded speech, but the voice cloning tools to create an AI version of your voice are amazing. I've used AI voice-cloning for this. You clone a 30 second clip of your voice then use an AI text to speech tool such as Chatterbox to create an AI voice of you. You can then upload your text script and the TTS tool will speak in your voice. You can tweak it for emotions and speed and nuance. Takes a bit of effort to understand the tools but they work really well. From a workflow angle, these voice cloning tools work well because it means you don't have to spend time perfectly recording your voice - getting the levels right and worrying about background noise and all of that 'live mic' work. The voice clone tool pops out a perfect sounding audio file based on your text. Just feed the script to the tool and out comes your perfectly recorded audio with your voice.