@Nickd1 not sure if there is much of any help. You may want to check out NOTICE: Unexplained Data Loss Issue and read through everything Mattches says at the top, including the little drop down box areas he has of info to gather and basic reading. I’m referencing screeenshot below, where you would click on each to expand it on his post.
Unfortunately, not a lot of people are providing feedback and there hasn’t been anything to track these losses back to. While nobody from Brave has given up on trying to figure it out, they are currently at a loss and haven’t been able to make any progress on it (last I spoke to some of the developers).
Not sure if @Mattches might have any further updates on it. But at least tagging him in so is aware it’s still an ongoing problem