Not sure if anyone else is having the same problem? 

Was using my phone, as normal, nothing new was immediately installed prior and it just went blank and then went into reboot loop.

It did come back on and say "optimising apps" which makes me think it's a Samsung update issue.

I've tried wiping the cache through the back door menu but nothing is working. I'm really reluctant to factory reset if there's a simple fix. It also won't let me into safe mode but not sure if I'm just doing it wrong or the phones not giving me enough time to do it between restarts.

Any advice?