I'm not entirely sure how the webextension would break your profile unfortunately. This webextension doesn't do anything on its own until you configure and activate it. There are also warnings about enabling non-cookie site data cleanups (cache, indexedDB, localstorage, service workers) should you choose to enable it. The webextension doesn't utilize any configuration sync yet, so you would have had to export from the old device and reimport the configuration manually.