When you say you upgraded the app - can you give us a bit more info? You upgraded from what version to what version? I'm guessing from Lightroom Classic to Lightroom(Desktop)? Screenshots of what you're seeing/ not seeing may help as well.
With the Lightroom mobile app, the most common cause of losing presets and photos is that you've logged in with a different Adobe ID than you'd used previously. Double check that the Adobe ID you've used to log in recently is the same ID you used before the update.