You can try connecting to a computer to transfer your files, but I believe the phone would have to be unlocked for access--maybe not, doesn't cost anything to try. Absent that, your backup would be unreadable from the cloud, but you could recover on another Samsung phone. So, if you replace your non-functioning phone, you can restore your backup to the new phone.
Have you factory reset your phone? You should try that and then restore your backup. Your issue may be a corrupted operating system, rather than a failing phone.
