Yeah. Like a phone in that condition is going to boot into download mode magically
You've been here long enough & seen enough of these to know there's only one fix for 99.9999% of them (& this one is not one of the 0.0001%).
OP - one/more components on motherboard dead = replace motherboard - Samsung service centre for new board (expensive option), source 2nd hand board yourself online (Google search) & either swap yourself or pay local mobile repair shop to do the swap (cheaper option).
Anything else anyone tells you is just giving you false hope where there isn't any (and I really wish people wouldn't do that on here; why not just be honest with people from the getgo ?).
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?