anything free that changes voice to fix old videos?

I sometimes get old educational videos with terrible audio quality. Cleaning them up with effects in audacity is not enough, they sound terrible even after that. There is some audio program for changing your voice that intrigued me but it won’t seem to work with audacity and is not free. While a robot voice is easy, what I liked about this is it kept the inflections and sounded like a real person. Is there anything else like this which can do the same thing which I can either use in audacity or process from a wav file?

Adobe Podcast enhance may be worth a try …

Is there a tool to do it with AI voice replacement?

I did try that btw, but it doesn’t do nearly enough for these files. I was able to do a better job just using audacity tools. But it still isn’t even close to 100%. I’d much rather have all new voice if possible. The voicemod thing would be good if it were free and actually worked right, haven’t seen something else like that which maintains the tempo of the original speech but that is meant mainly for podcasts I guess. And costs money, which is out because this is just for free yt educational videos.

How about cleaning in Audacity, then applying Adobe enhance ?.

It would be possible convert from real speech => text, then text => AI speech,
but the inflection (and lip-sync) would be lost in the process.

Captions would help, whether or not you process the audio is processed,
YouTube does caption videos automatically,
(but in my experience its speech => text is only ~90% accurate).