I had a quick look and removal of the inductors I had in mind wouldn’t truly isolate the ICs from the SYS rail to rule them out, only 50% which wouldn’t be concrete enough to say they weren’t causing the issue.
Here’s the location of the inductors anyway if you want to try anyway, then after removal see if the 300ohm short to ground has cleared back at the 2R2 coil… though I don’t think it will.
Take a close look for any junk/bent pins in the backlight connector or LCD connector, it’s feasible if that was the case it could subsequently pull SYS down via the respective IC, that being the 8316 IC via the LCD conn or UXYZ (Backlight IC) via the bcklight conn.
If that’s not the case, my best guess would be junk under one of the BGAs on this rail. Might be a good idea to measure resistance to ground like earlier at the coils and surrounding components of the Max IC below the SoC, this is the most prone to liquid damage and would be my first guess.
Unfortunately 300ohm is too high to generate any meaningful heat, else I’d reccommend hooking up your PSU to this rail at 1V (no greater, in case there is a crossed line elsewhere) which leaves the good old fashioned… pull every IC on this rail, though reball experience (stencils, solder paste etc) is needed