Curious to know what brave version are you using? I’m wondering if it has been updating automatically. You can check using brave://settings/help or click the hamburger menu in the top right of the page and click About Brave towards the bottom of the list.
You can save your current Brave-Browser folder as a back-up and restore it if something goes wrong. This will save your rewards and profiles. You can find the path to your Brave-Browser folder by going to brave://version and copying the Profile Path information to Brave-Browser in the path displayed. Don’t know about the history and tabs but you can also save your bookmarks separately by going to brave://bookmarks and clicking on the Organize menu in the upper right and exporting your bookmarks.