Can't boot and Odin isn't letting me flash stock firmware

Basically I wanted to try the sac23 edge rom on my flat gs6, i noticed it was a 5.1.1 rom so i updated ota and then rooted and installed twrp for 5.1.1 then I went to install the sac 23 rom and then it just hasnt booted since, tried with a kernel too and even factory wipe didnt work, then i flashed another rom that is the xtresolite universal edition, everything usually works except mobile networks so i flashed that to try to get it to boot, still wont it just hangs at the samsung galaxy s6 logo then eventually turns off, the charging logo doesnt even go to charging just the charging symbol. After that i decided to flash stock firmware, doing so i realized that i wouldnt be able to use the 5.0.2 firmware which didnt work, so i downloaded the 5.1.1 firmware and i have two, one ends in of7 and one ends in 0e2, both have not worked and im getting worried, i bought this phone because i accidentally destroyed my s5. so i had to pay like full price for this phone and reallyyyy dont wanna buy another pleasseeee help :(
Thanks (:
Edit: I have a sm-g920p and flashed a sm-g925p rom because i heard you can do so with a kernel