@george
The first run after receiving the laptop was actually fine. It was then unpowered for like a month and a half and then I ran into the troubles described in the first post (unable to initiate the boot sequence, green LED on the base board).
I then brought it to a local repair shop and the repair guy identified that it required mechanical pressure to boot because of a failed keyboard controller chip (will later post/send photos)
After the repair was completed I managed to use the laptop for a couple of days: I used the pre-installed Ubuntu, upgraded some packages via apt upgrade and used it to run vscode, web browser (+video playback), compile a few apps and run some OpenGL stuff. According to the thermal sensors read from /proc, CPU heated up to 80+ degrees for several hours in a row but I noticed no issues until the day before today.
Regarding the repair shop report, the reason this time was some electric components failure (2 resistors/capacitors on the CPU board, one malfunctioned, the other blown out and making the noise, will later post photos); repair service man told me overheating might have been the cause for it.
I asked to replace the bronze+graphite heat sink with a solid copper plate after electric components replacement, hope it helps next time.
Could you please suggest what data should I collect (like sensor values, command outputs, diagnostics reports and so on) which could help in debugging the cause? Also, a question coming from the heat sink design: is it fine to overheat/overload the v10 laptop for extended periods of time? I read about automatic throttling so I assumed it should be fine but then the circuitry has failed.
As for the inconvenience — I presume that i've got a laptop out of a first batch in series so I was actually expecting to bump into some kind of an early production issue with that, it's fine. Thank you for your attitude and for what you are doing, really appreciate it
Will send an email tomorrow or in a next couple of days

Update: brought laptop to the local service. Diagnostics identified that the keyboard controller chip was shortened thus not allowing the laptop to boot properly.
3 weeks of waiting, chip has finally arrived and got replaced. All fine, well, was fine for 3 days; the laptop heated up to 79-80 degrees (according to /sys/class/thermal/thermal_zone*/temp values) under medium to high load (video playback and 3d applications) but I guess that's okay
Then the chirping electronic noise appeared under load (cold boot then load test). I powered the laptop down, let it cool down and powered on again, the chirping noise began immediately under the load; shortly after I saw the same visual artifacts (horizontal bars) like in the 1st image in this topic.I managed to boot it once again, and it froze after some 5-10 minutes of video playback.
Can still boot it, but there seems to be a trouble with the power circuitry or something. Brought it back to the repair shop, now waiting for the diagnostics report.
The laptop was from v10 issue (ordered late 2023). Keeping you informed as I get the new details

Update: after careful examination I found a stain of lead colored grease on the baseboard below compute module.
After wiping it out I saw that the board underneath has a slightly brighter shade of green. Not sure if that's the mask reacted with that grease and lost its color or it's I accidentally damaged the board during transportation.
Now it boots (blue LED, coolpi logo, Ubuntu boots) only when holding down Loader key, green LED lights constantly and blank screen otherwise. Still looks like either a crack in the board or contacts misaligned/poor contact since mechanical pressure makes it boot.

Do you provide some kind of baseboard PCB layout or service manual, and do you sell baseboards separately? I will try to take laptop to local repair shop for diagnosis and update with the results.

Full size 1

Full size 2
The laptop did not boot (black screen, green LED near the CPU);
Found that it boots while holding it with one hand by corner. Thought that it is because the upper case metal plate might have been touching electronic components; disassembled, cut screen protector film into some electric shielding and put it under the main board and between the compute module and the motherboard; cleaned contacts with alcohol, put and screwed everything back.
Now it booted but froze on the login screen immediately after I pressed spacebar. After freezing, applying and releasing pressure removes or puts the graphics artifacts back on screen, the laptop does not unfreeze until reboot.
Rebooted fine, can actually log in, but the laptop freezes every time there is a slight pressure around the spacebar area.
What might my problem be, and what should Ilook at further to diagnose and maybe fix it?