On Dasharo (who worked on support for MSI boards) has pre-flashed motherboard for sale on their website, but looking at the price it's expensive, but it comes with some support.
The problem has been solved, it's caused by mesa's video decoding package, I will answer anyway.
Yes, VCN (Video Core Next) column stays at constant value while playing video (3% for VA-API with mesa, 5% for VDPAU with mesa, 0% for libplacebo), GFX fluctuates between 0% and 1%.
Just playing a 1080P video (not even a high bit rate one) is enough to make GPU fan go spinning, disappointing.
Turns out in my case it's mesa driver causing my problem, after removing mesa's VA-API and VDPAU drivers VLC can still play things just fine, CPU is at 2~3%.
Through some more testing, I found out mesa related hardware acceleration package can cause these power surge, on Archlinux it includes mesa-vdpau and libva-mesa-driver.
If I don't have these package installed, VLC reverts to libplacebo which doesn't seem to cause more power usage.
My worry s that playing a 1080P video need 30 watts (assuming amdgpu_top is not wrong), I would like to move that workload to integrated GPU, which I enabled in BIOS.
Thank you for your answer, I can confirm by switching to VA-API it lowers my power usage by a lot (from 45 to 20~21 watts reported).
I will give a version of event that I have observed, simplified (a lot of things glossed over), and maybe inaccurate.
LinusTechTips (one of their employees) criticized Hardware Unboxed and Gamers Nexus do banchmark videos in a lab tour video (on MurfsGaming channel), HUB fight back on Twitter(X), Linus (the owner of LMG) double down in their WAN show saying some creators are unprofessional, this leads to Gamers Nexus doing a long video point out how unprofessional LTT is (many errors in their videos).
In Gamers Nexus's video, they shared a story that a company send their working prototype for LTT to review, but LTT doing the testing wrong (use the prototype with incompatible hardware), then sold the prototype for charity when they have been requested to send it back twice, screwing the startup company on top of giving inaccurate test results.
Linus (the owner of LMG) fight back in forum post with no apology (basically spraying gasoline on fire) and made up fake event saying they have already agreed to compensate the startup company.
Gamers Nexus says in their next video that they communicated with the startup company and LTT only contacted them two hours after previous Gamers Nexus's published, debunked Linus's claim that they already made a deal to compensate the startup company.
An ex-employee publicly talking about the time she works at LMG, bait-and-switch working contract after she moving all the way where LMG is, sexism, sexual harassment, threats, unhealthy work environment.
I see 1823 as in the past when it's currently 2023, didn't know about that wasn't a English word then .