As far as firmware, the link to sammobile I gave you before are the best routes for that. Bootloops I've been stuck at were only at the main boot screen, the Samsung animation screen I had to just leave alone until it fully loaded which did take a few good minutes. A lot of sweat during those minutes lol and you may need to wipe your device once you're able to get back to recovery, constantly flashing on top of flashing without any wipes could cramp space on partitions or overwrite data in ways that just give problems.
Fully wipe your device, flash a stock firmware from sammobile (preferably the one your device came with, make your best guess) , clear your cache and dalvik as you finish stuff up, than let it load up. Than come back to this thread and follow instructions. I hate you're having such an issue with your device, yet I feel like it shouldn't be this complicated lol
Good luck again man.
Mine doesn't even get into that animation screen. It kept stuck at that samsung logo, and I couldnt turn the device off either.
How could I "full wipe" my device when could get into the recovery mode?
And all the fw I have tried flash got error at "NAND WRITE!! system.img".
Never fell like giving up like this.