It’s a fight against challenges to his power first and foremost.

Oooor he's just purging potential rivals like all really successful dictators.

to avoid the state from falling into corrupt hands

That's decades too late

Because nothing says reasonable measures against corruption like secretly disappearing people without any sort of announcement leaving the world to blindly guess what went down. A lot of other authoritarian leaders at least bother to make up stuff, but not even that here.

I also think it's interesting to say that in his 70s it makes sense to be harder on corruption, why wouldn't there be a consistent pressure on corruption throughout?

If it is related to his age, it would make more sense that he is experiencing some mental decline that drives him to be more aggressive or that he wants to ensure his intended successors have the least opposition to worry about.

I might get down voted too but I think i follow what you're talking about

I had to look up a source again but I remember reading that they were having major equipment issues like rockets getting fueled with water and stuff like that.

If that is the case, then something like this doesn't sound that surprising

Found my source