Lightroom App Update Wipes Users’ Photos and Presets, Adobe Says they are ‘Not Recoverable’ August 20, 2020 https://petapixel.com/2020/08/20/li...-presets-adobe-says-they-are-not-recoverable/
Holy crap sounds like one of the biggest blunders ever! And yes, always make sure to back up stuff, perhaps using the cloud isn't such a bad idea after all. I have to admit, I'm too lazy to make back ups to external drives, I believe I would make back ups more often when using services like Dropbox.
Since I almost lost all my marriage pictures a few years ago, I keep backup of my data on two cloud services and an external hard drive... If it were my profession I would have even more copies.