illustrator previous version

[#1]

I want to install the previous version of Adobe Illustrator because currently, I have version 23.5 and when I drag my artboard around I see some delays so I want to downgrade my Illustrator version to 20 so that I have smoother performance but to do so I cant find other versions option beside Illustrator in the creative cloud so can u guys help in this regard?

[#2]

I want to install the previous version of Adobe Illustrator because currently, I have version 23.5 and when I drag my artboard around I see some delays so I want to downgrade my Illustrator version to 20 so that I have smoother performance but to do so I cant find other versions option beside Illustrator in the creative cloud so can u guys help in this regard?

[#3]

Only the current version and immediately previous (24 & 23) are available officially through Adobe.

There are direct downloads for a few more versions on ProDesignTools' site. CC2017 seems to still work:

https://prodesigntools.com/adobe-cc-2017-direct-download-links.html