Debug tips when you hit any issue (fail to boot/ keep reboot ...etc)

Jetson nano was working fine 2-3 days ago when plugged the power supply after a few days. First Nvidia screen appears, then it turns off the display & doesn’t boot, but the green led is On. And I looked at the forum and tried solutions like switching power supplies for boot micro-USB and 5V jack, the processor was working fine checked with power sources, reflashing the SD-Card many times with different versions, then tried to connect Jetson Nano over serial using minicom on Ubuntu, also tried to recovery & reset through J40pin,tried to boot with USB also but results show negative. Any solutions, suggestions & how do I get the support if it’s a board issue.
Here is the report logs I am attaching bellow:

[ 1.168656] tegradc tegradc.1: dpd enable lookup fail:-19
[ 1.190672] tegradc tegradc.1: dp: aux write got error (0x10000100)
[ 1.196994] tegradc tegradc.1: dp: Failed for I2C write addr:80, size:1, stat:0x10000100 [ 1.217386] tegradc tegradc.1: dp: aux write got error (0x10000100)
[ 1.223683] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100
[ 1.237036] tegradc tegradc.1: dp: aux write got error (0x10000100)
[ 1.243322] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100
[ 1.256362] tegradc tegradc.1: dp: aux write got error (Ox10000100)
[ 1.262653] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100
[ 1.275981] tegradc tegradc.1: dp: aux write got error (Ox10000100)
[ 1.282265] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100
[ 1.290543] tegradc tegradc.1: dp: failed to exit panel power save mode (Oxfffffff2) [ 1.326963] imx219 7-0010: imx219_board_setup: error during i2c read probe (-121)
[ 1.327032] imx219 7-0010: board setup failed
[ 1.350851] imx219 8-0010: imx219_board_setup: error during i2c read probe (-121)
[ 1.350909) imx219 8-0010: board setup failed
[ 1.414870] tegradc tegradc.1: dp: aux write got error (Ox10000100)
[ 1.414874] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100 1.419851] tegradc tegradc.1: dp: aux write got error (Ox10000100)
[ 1.419855] tegradc tegradc.1: dp: Failed to write DPCD data. CMD 0x600, Status Ox10000100
[ 1.424829] tegradc tegradc.1: dp: aux write got error (Ox10000100)
[ 1.424832] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status Ox10000100
[ 1.429660] tegradc tegradc.1: dp: aux-write got error (Ox10000100)
[ 1.429663] tegradc tegradc.1: dp: Failed to write DPCD data. CMD Ox600, Status. Ox10000100
[ 1.429666] tegradc 'tegradc.1: dp: failed to exit panel power save mode (Oxfffffff2)
[ 1.429669] hpd: ed id read prepare failed
cp: not writing through dangling symlink ‘etc/resolu.conf’
[ 1.898988] cgroup: cgroup2: unknown option “nsdelegate”
[ 3.103394] using random self ethernet address
[ 3.118761] using random host ethernet address
[ 3.822117] random: crng init done
[ 3.825550) random: 7 urandom warning(s) missed due to ratelimiting
[ 4.027635] using random self ethernet address
[ 4.042287] using random host ethernet address