If you are a paid subscriber, your presets are backed up to the Lightroom cloud and would remain available as long as you sign back into your paid account.
If you are using the free version of the app, you would need to restore a device backup from a time when those presets still existed inside Lightroom. Only restoring a device backup can help restore presets to a free Lightroom account after the app is deleted or when a device is reset like yours.
Is it possible you favorited certain Discover posts? That might help you find presets you liked so you can download them again.