Repair question on n3ds xl. Where did I go wrong?

Hi, so I'm not new to repair, mods etc. I am repairing a n3ds xl. I bought second hand at retro game store. When I first turned it on it was perfect. Aside from cracked face plates and the touch screendidnt work/couldn't calibrate.So I dismantled carefully and cleaned the interior and the digitizer. Still wouldn't calibrate.

So I replaced the digitizer. Bam it works. However I had to replace the face plates at the same time (less messing with the interior trying to AVOID bricking the damned thing). When I had turned on the 3ds and calibrated the screen I was able to use a multi game cartridge and it worked great.

After a few minutes I realized I had incorrectly reinstalled the volume and 3ds buttons. So I went to go fix that. I go to turn it on, blue light and backlights for screens come on then POP and nothing.

I trouble shoot this assuming I loosened a cable so I go searching. I can't find anything. I put it back together and go to turn it on. This time NOTHING. no backlight and no blue light. It charges though. Orange light will come on.

I bought a new button board and new button board cable. Just installed it and same thing no screen, no blue light, charges with orange light.

What's my next step? Give up? Replace more parts? Just dismantle for parts and get a new one?