%localappdata%\Titan\Archive

However, that said, you aren't likely to be able to load those saves unless you some how manage to track down an compatible older version. But that is where they are stored.

Any data that was able to be transferred to the latest version has been during the archiving process.

I did find them in there - but as predicted I am not able to restore them, it just archives them with the same message.

I'm not sure what was supposed to be transferred but I lost all progress on my campaign that I was 20+ hours into.

I'm assuming it's been quite a long time since you last played?
The game's last update was a year ago this month, and they likely would not have invalidated the saves for a minor version like that.
So, were the saves during the Early Access era? Cause that would explain it.

No I had played the night before actually

That's... odd.