So- I don’t know if this will help everyone but it helped me!
Some background;
The game was running fine until the update and then it was lag city (bitch. Lag lag city, bitch.)
But even the system itself seemed like it was getting dragged down with the game. The whole system was sputtering and taking forever to load- then I got the blinking blue light.
The solution-
For me, what helped was factory resetting the console and manually updating the system via safe mode. You’re gonna need a usb with the newest PlayStation update on it (that they walk you through on the website.) Then once you install it and get your system back up and running, it should run waaay smoother.
I’ve seen a few people sharing my PS4 woes so I thought I’d share! Hope it helps!