@Hqnicolas Take a chill pill dude. I am not trying to prove/disprove anything.
I am simply suggesting that the board may indeed be of 8/64 config. Sometimes, due to screwed up u-boot, not all the RAM is reported correctly. And here, I can see that adding up the memory (3.8) and zram (1.9), it comes to around 6GB. Hence, I suspect the memory is still there, it's just not reported correctly because of the zram/swap thing. Removing the swap/zram completely may indeed show it to be 8GB.
On your note of TV boxes being unreliable, I never refuted your claim. I agree about the unreliability. At the same time, I own two of these x88 pro20 boxes (8/128 and 4/32) and looking at the chips and the markings on the board, I have certain confidence that it would be an 8/64 indeed.
And, I own a total of 4 tv boxes, and a total of 4 sbcs (2 raspberry pis, one orange pi 5 plus, 1 starfive vision V 2), so I know what to expect and how wild things are out in the tv box world.
I am sure you also know better than to claim to be the final authority on declaring all tv boxes as "unreliable"