The direct cause of the explosion is very well-documented. There is no mystery to what went wrong in the reactor, no place for a conspiracy to enter into it. The only places where people debate are where you should lay the ultimate cause, e.g., the technical design of the plant, the Soviet bureaucracy, the plant operators, Soviet nuclear culture, what have you.

No expert that I have known or read has ever entertained anything like a conspiracy theory about it. If you are suggesting it was some kind of deliberate sabotage, there is literally no evidence for that, nor any plausible way that would work.

Baseless conspiracy theories for their own sake a poor use of one's time alive. The world is full of too many interesting and important mysteries and problems to worry about fake ones.