How to download older versions is described here, for example: https://www.competethemes.com/blog/download-older-version-plugins-themes/
However, these are not so different that I could understand your actual concern. What exactly is your problem? Maybe it has nothing to do with the theme.
thank you! I no longer have the editor option under appearance. And cannot see where to edit templates
I was able to download and replace the older version, but I am still not able to edit templates. I did remove an app called WordPress editing tool and that got rid of the error message I was receiving. I really would like editing back.
The TwentyTwentyOne theme does not have an editor like modern FSE themes. You can only change settings there using the Customiser or by changing templates using a child theme.
Are you possibly confusing the theme? Because what you are looking for is available in every FSE theme, e.g. TwentyTwentyTwo, TwentyTwentyThree or TwentyTwentyFour.
