Overheating device with random apps spiking CPU usage

Few days ago my phone has started overheating and burning through the battery like crazy. I don't use it too much, and it used to last 1.5-2 days, now it's dead in 6 hours. I've installed System monitor lite and it's showing that several of my cores are constantly at extremely high usage (over 80%), and various regular applications like Gmail and LinkedIn are shown spiking the CPU up to 20% each. I expected a single app to be doing something stupid, and after seeing which one it is, it would be simple to just remove it, but that's not the case. It turns out that a bunch of regular apps that I haven't opened in days are going crazy. Here are some screenshots: So, any suggestions besides doing factory reset? The phone in question is Xiaomi Redmi Note 4 running original MIUI without root. ----