I'll keep this updated in case anyone else has the same problem
it turns out this is not just a problem for this model, it's with all old LED TV's, the screen is lit by horizontal rows of LED lights and at some point the lights go out or something on the power board does.
found this resource for my specific problem on any LED tv:
step 1: unplug it, wait 2 minutes then press and hold the power button for 30 sec, check if it's fixed.
2: ID if it's the power board or the light strips, then order and install parts
this vid is for my TV the
you can watch him get the connectors open so you dont break yours and just get an idea what you're looking at when open it up and so on.
It's a bad idea IMO to fix a single LED or a single strip like this guy bc if
one of your lights is bad, the others might be next and you've already got it open.
-make sure you get the right parts for your tv ofc
-buy the suction cups if you need to take the panel off (to replace LED strips) , this will help you not drop it and break it.
update coming when the parts arrive.