I think I see your issue and might know a solution, Flyer.michael.
First, you seem to be looking for a 0x0 Knox root. See below, as I think this method will work for the 605 LTE model:
Second, you wanted some kind of apps to SD option. Looks like there are some options on the Play Store, but you might want to look into this one:
This requires root, but it seems like you can move / link apps to your SD as needed. Again, not sure if this is what you were looking for but it might be worth a shot if you're rooted, not sure if this even refers to what you were wanting. I did read on some other forums that Samsung has some issues with Apps 2 SD and it may be a bigger problem than can be fixed with a root method.
Lastly it looked like game resolution was disappointing for you. You might be able to try one of the following:
---- This option might not be what you were wanting, as it causes some other issues.
---- Xposed has a module Xposed App Settings and it seems like from within that you can change the resolution on a per app basis. Maybe that will work. DPI will not effect game resolution, but the resolution change option might work. Not sure if this module works for our tablet or not... but again, worth a shot if you feel like it.
I haven't used the Xposed module on this tablet, as I refuse to root until my 600 WiFi model supports a Knox-free root method. I chose the WiFi model as I have set up an automatic bluetooth tether for data connection since I always have my phone on me. Figured it was worth saving $100.
Anyway, I hope this might help.