default system file size of a fresh tablet?

I was trying to root my samsung galaxy tab e 8.0 (sm-t377w) and i ended up bricking it via odin.I managed to flash it with another copy of the firmware via odin (virgin/bell mobile now i assume its t-mobile currently ) the firmware files didnt specify carrier so i downloaded the first one. well after rebooting i tried downloading an app and it said the memory was full but i hadnt downloaded any apps yet. i booted into restore mode and wiped cache and reset it to factory settings/wiped something else and rebooted it. it started up fine and says 6.5g/16g in settings and from my understanding is this model does indeed have 16g. my question is do the system files of a fresh tablet really take up 6.5 g or did i flash the new system files over the old system files and if thats the case, how do i go about fixing that?

i dont care what carrier its connected to since i dont have a sim chip in it and i dont plan on putting one in it, im just worried that maybe i flashed one system over the other and its taking up twice the space. i hope i made this post understandable