I tried using Synaptic but it's only listing the current version so I guess I can't use that.

As for the system backup, it's a few days old but I don't think I did anything with it that I couldn't replace. I just mostly don't want to because, assuming that Brave is the only thing that broke, Firefox works fine still. If I can't get Brave or another Chromium browser to work, I can just use Firefox for the time being and hope the issue gets fixed later. Although, I'd need to know how to set up and use multiple Firefox profiles. which I used to know how to do on Windows but I was never able to find out how to do this on Linux.