PCH-1104 not turning on

[PoisonedShiitake]

Sup guys, I need some help to figure out what's wrong with my PS vita fat, I bought it a few days ago and it was working good except for some water damaged right stick for which I already ordered the replacement (luckily, damage didn't affect the right board nor any other components as I checked by connecting left stick on right's socket and worked perfectly and ofc I cleaned it thoroughly with isopropyl alcohol), but, after a few days I tried to power up the console to play some og mhfu, but it didn't turn on, also, when connected to AC charger, PS button blinks twice and turns off until charger is reconnected, here's what I tried so far to diagnose the vita:

• Leave charging overnight with original psvita adapter.
• Trying to boot to safe mode.
• Unplug battery connector for 30 seconds to 10 min.
• Changing AC adapter (5V 2A).

After that, I decided to dig more into the technical stuff and opened up to console:

• Battery voltage is 3.98V and is charged (tested by powering a 15W LED bulb).
• Charging fuses (both channels) are okay.
• Soldering two wires to the battery pads on the main board and connecting them to a power supply (4.2V 2A max) but didn't turn on neither.

That last thing I tried is what makes me think that is the main board which is having issues. Now, my question right now is: Who is the most probable suspect here? becuase, I don't know much about the vita's power management so is really hard for me to check was exactly wrong.

So, I'm open to suggestions, thanks in advance for anyone who is willing to help.

Edit: I forgot to add that the "reset battery combo" also didn't work, the current consumption when the console was plugged to the power supply was zero and when connected to a PC, is not recognized by neither device manager (windows) or lsusb (Linux).

Also, I managed to get rid of the EMI shield on top of what I suppose is the power circuitry, there, I found a couple of fuses that were working perfectly too. I'll leave a photo of the power "area" as an attachment.