Software Update

I have a MacBook Air 2014 running 10.9. Its never been updated. I need to update it to at least 10.13, but all the way to Catalina should work. Currently when I run the Catalina update through the App Store it runs for a few minutes and then stops with an unable to complete the operation error.

Apple support helped me delete the unfinished process and restart the process. I've done this three times. No success.

Is there a place I can download 10.10, then 10.11 etc. and incrementally do the updates?

Any suggestions on how to get this laptop up to date?

Thanks much,

Dan