No obvious need to reinstall if you didn't use ssh and expose it publicly and are not a politically important person. All signs suggest that it was a nation state attack, and you are likely not a target.
But it's unclear if earlier versions are also vulnerable.
And if it did nasty things to your machine, how do you make sure that the backups you have do not include ways for the backdoor to reinstate itself?
I don't backup the whole system, just a specific list of things in /home.