Welcome to Android Central! It's hard to tell with these kinds of off-brand devices, because it could be due to faulty hardware, firmware, or app conflicts.
Try booting into Safe Mode, which prevents all 3rd party apps from starting up initially. Once in Safe Mode, see if you get the crashes. If they don't happen for a while, then start opening apps one by one, waiting a little while in between to see if the crashes come back. On most Android devices, you can get to Safe Mode by pressing and holding Power until the Power menu appears, then press and hold the Power Off option until you see the Safe Mode prompt. Tap OK to continue.
To get out of Safe Mode, just reboot normally.