Messed up my recording can it be fixed

I recorded some audio off a portable recorder for a co-worker and we had to record it at 2x speed off the device since it was a 10+ hour file and we had an 8 hour workday… more like 6 after coffee and bs. Then being noobs we adjusted speed by half to slow it down to normal or so we thought because you know adjust speed sounds like the right thing to do to a normal person. Well it made the speech so slow and voice so deep it is unrecognizable. Later read we should have adjusted tempo..… so adjust speed to original and adjust tempo to -50 but now there is a bad echo/distortion it is not as unbearable as the first attempt but it is bad. Is there anything I can do or did I jack the recording by adjusting speed back and forth.

Thanks in advance for any insight

If you still have the original “too fast” recording, then I’d suggest that you try Change Tempo with and without the “Use high quality stretching (slow)” option selected. That setting chooses one of two time-stretch algorithms - in most cases the “high quality” algorithm gives best quality sound (particularly on small tempo shifts), but in some cases the “normal quality” option sounds better. Whichever sounds best is as good as you will get with Audacity.

If you don’t still have the original recording, then what you have now is likely to be as good as it gets.