It's just a logic loop. Which is fine but we need to work that logic loops into conspiracy theories too.
The hypothetical argument is that if the hikers were up to no good like the stupid argument of giving radioactive clothes or secret information to some spies from the west , we wouldn't even know about the dyatlov incident. At all, the KGB or whomever would of just sealed the case , your children were found dead , here's the ashes. No questions . They would just erased the whole incident, they wouldn't waste time of processing films, putting them back in cameras, staging the cameras firms back into the cameras , back into a tent , get ivanov to give these films to the students to re-develope and then give them back to ivanov to then keep for the case files.
It's a pointless inefficient exercise, they didn't need to create a narrative through forging film negatives.
Let's think of the logistics . Find some hikers, dead or alive around the 1st of February, kill them, move their bodies, stage a campsite , remove cameras, get back to civilization, develope the films, re edited them back into undeveloped films , wind them to the right sequence in the film sprocket without light exposure, put them back into the tent to be found by random searcher's. The plan for that to go correct is off the rational scale. Then we have the footprints without other footprints.
The logistics for the searchers was difficult let alone any possible stagers. That's food, heat , fire , cutting trees , the cold, the winds , helicopters breaking down, not being able to land etc.
Where exactly is this window of opportunity of outsiders to come to the pass where there's nomadic Mansi hunters, student hikes , snow that leaves trails and all sorts of problems that stagers would incur?
Even any stagers have to run their own logistics , that's food , fuel , pilots , medics, saws, tents, helicopters , skis, shovels , special services for this camera film developing thing, a team of thinkers to build a narrative, where to stage tent, what to do with diaries, rewrite them? So on and so on.
I do not think the soviets had such a facility to react in such a way for some secret special service to reconstruct a death scene in a such an elaborate way in the middle of the Urals in winter.