have you check your background processes of your system?maybe your system is utilizing some heavy resources that's why after playing fortnite for couple of minutes your system get hanged and choppy, disable or uninstall unusual programs.
CPU, graphics card, or case fan failed or became unplugged, reducing air flow. Tune Up Heat Sinks: If your CPU is overheating, its heat sink may not be seated correctly or its thermal paste may be old.
in this budget you could buy ipad ipad which is very good for watching HD netflix shows, playing games and doing some other general purpose work too, the battery timing is also good as compare to android tabs
it totally depends on your interest, like i 'm RC planes hobbyist, in my free time i use to fly my RC planes in nearby open ground area, you could also go to local rc or hobby store and buy some beginners stuff.
go to skype settings and check sounds and notifications tab, and check whether it is muted or the sound is lower, also check your pc settings for notifications sounds.
try some other ad blocking extension if Adblock is crashing, check extensions on safari browser and make sure to see ratings and reviews before installing.
before uploading your video, always check the youtube video quality settings, maybe it is lowered from there, also use some video editing software to render your videos.
After resident evil update, the game is causing too much FPS drop and lag, try to lower your graphics settings and check again, the same issue is happening on Android phones and iPhone.
I usually buy 15,20 games per year, I mostly buy second-hand games which are 50% less from the actual amount, i bought online from eBay or Gamestop, always look for black Friday deals too.
some application may be consuming too much battery, look for some background processes too, if there isn't any high power consumption, try to get your battery replaced maybe the cells are weak as it is 2011 model.