tl;dr: Recently keep getting the "checking system storage" option, tells me it can't start and to insert a USB with the latest update. I cancel, it shuts off, then I can immediately start it again without issue. Not sure why or if I should be worried.
For the past few months or so, I've noticed more and more issues with my PS4 (got it in 2015). A couple of years ago, I upgraded the hard drive to a 2TB one so I could store more games on it, etc. Lately it seems to be crashing a lot, usually when I'm done playing a game and trying to turn it off, but sometimes it will crash during a game and shut down (i.e. playing Uncharted 4 online with a friend). Other times it'll just freeze for a minute or so and go back to normal (when playing RDR2 and I bring up the pause menu to try and save, it'll pause and bring up the red bar on the side, but no menu options will appear for a minute or two. After that, all the menu options will appear and I can save properly, etc.)
The past few days however, whenever I was done playing and turned off the console safely (PS button - close application - power options - shut down), it'll take a few minutes to actually shut off. When I start the console the next time, it goes to the "Checking system storage screen" and then says I should input a USB with the latest system update (the console is already fully updated). However, instead of doing that I just hit Cancel and the system shuts off. Immediately after that, I press the PS button on the controller and the system seems to start completely fine.
Any ideas why this may be happening? The console hasn't suffered any physical damage (hasn't been knocked around or dropped, etc.) and I try to keep everything updated properly.
The errors I tend to get are CE-36329-3 and CE-34878-0.
Any help or insight would be greatly appreciated :)