yep its really my motherboard problem

, lmao F' that lagiacrus XD, u sopposedly leave him alone tho cuz my current rank isn't that high or switching my armor set based on his weakness

, umm should i try to switching to emunand setup method? , can i use the 128 gb micro sd, if i switch to emunand ?, and can i keep my game and save if i switch to emunand?
In one of my responses to fatsocat in that
other thread, there was another post explaining why having EmuNAND is not a good idea especially on SD cards with larger capacities.
The reason he needed to switch over to EmuNAND was because the
eMMC Status Checker revealed the eMMC (NAND chip) on his New 3DS could no longer reliably be read from and written to. To see what the eMMC looks like on the New 3DS XL, look for the Samsung component boxed in
yellow at step 13.
That chip is what holds the custom firmware and 3DS firmware. It's the analogy equivalent to a computer hard drive containing the [ Windows / Mac / Linux ] operating system. In the case of fatsocat, he could get away with substituting the microSD card to act as a secondary or backup NAND.
Unfortunately, because your n3DSXL passed its scan run in
eMMC Status Checker, that means a different part on the motherboard has failed. The likely culprit is the RAM; Fujitsu component boxed in
green. The
RAM shares similarity to the
eMMC and
SD card as they're all computer/flash memory technologies. The best way to describe the difference between eMMC and RAM would be like having a large pot of soup and a bowl, where the eMMC is more like the pot and the RAM is to the bowl. Both are similiar in that they're containers but their main purposes are different.
You would much rather use the pot to store hot soup throughout the day while for the bowl to be able to scoop, hold in yours hand, and drink from. Let's say your RAM is like a broken or cracked bowl that'll hold the soup perfectly fine when sat down on a table, but the moment you pick up, tilt, and drink from that bowl, some of the soup leaks out of the cracks found along the bowl's brim.
While it's
technically possible to use a USB flash drive or SD card as virtual RAM on computers for basic and light duty applications, that wouldn't hold up in practice for the 3DS systems. See the (ARM CPU + PICA200 GPU)/SoC boxed in
red. It's not a coincidence these two components are placed right next to each other. Not only would there be the problem of no custom firmware programmed to utilize the SD card as the RAM, the distance between SoC & SD card, mismatch in read & write speed rates (compared to the RAM), and footprint (density of 256 MB vs surface area) means the SD card acting as RAM would be too bottle-necked in I/O and thermal stress limits.
***
Your n3DSXL reminded me of another person who had a n3DSXL with a nearly identical instability issue as yours (also ARM11 errors but slightly different readouts). All of the typical troubleshooting methods were tried to no lasting positive effects (ie, battery trick, quadruple reformat + H2testw, CTRTransfer, CTRTransfer (Type D9), SysNAND restore, eMMC Status Checker, etc).