there is no evidence of that happening. we know that engines did not get fuel. the other pilot asked first pilot if they cut of the fuel, and they replied that i did not (from the black box recordings afaik).

https://aaib.gov.in/What's%20New%20Assets/Preliminary%20Report%20VT-ANB.pdf

The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off

That is from the flight data recorder. The switches were moved.

In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so.

the other pilot asked first pilot if they cut of the fuel,

The other pilot asked WHY they cut the fuel, not IF they had done so.

I stand by my original comment. We only know

1. Two pilots
2. One cut the fuel
3. One restored fuel

That is likely all we will ever know. But the signs point to intentional action to disable the ship.

Air India Tragedy | The Pilots Tried to Save the Airplane

I've watched the video, he dismisses the AAIB preliminary report speed data as incorrect, THEN uses that same data to establish his theory about the engines. You can't have your cake and eat it too, you have to either use the data, or not use the data.

Mr Sabin assumes both pilots are of the same mind and any attempt to not crash shows the lack of self-sabatoge. Imagine a depressed pilot letting their intrusive thoughts win, just for a moment, and switch the fuel cutoff switches.... They are likely in shock, not believing what they have done. The other pilot goes into OH SHIT, SURVIVE mode, and the first pilot doesn't resist, or gets snapped back into reality and works together to try to save the craft. Many self destructive events are snap ephemeral decisions, its not impossible (suicidal people often call emergency services after doing self harm), so Mr. Sabin needs to account for this dynamic as well and not make assumptions about pilot mental unity. Heroic efforts to survive do not remove the potential of intentional action as the root cause.

We will never know the mental state of the pilots, we will only know what was recorded in the black box. The moment in time has passed, and the best outcome we can hope for is the normalization of mental health care for airline crew.

Mr Sabin's theory about a coverup could be credible, except wouldn't it be in AAIB's best interests to throw the responsibility on the plane and not the pilots? Why would they lie about the fuel switch data?

Confidently incorrect.

They know for certain that both fuel cutoff switches were toggled by a human being in the cockpit.