In different circumstances I have switched phones. Admittedly prepared with two live phones. First backup the old phone, then restore to the new one.
The process is Covered elsewhere here.
Now, no backup? I'm wondering if a) you are automatically backing up to Google drive, and b) if you can restore the app from that.
If you reset a phone to factory state it will ask if you want to restore apps from a backup. Never tried it but worth investigating.
PS this method fools libreview into thinking it's the same device too.