It's actually preferable for Putin for a few different reasons if it's simply a slow death because of unlivable conditions, than to have someone take him out back and shoot him quickly or something like that.

But yes, the system is working 100% as intended; this is a feature.

The Kremlin has denied any state involvement.

Of course they would.

Putin called Navalny's demise "sad"

Children being taken from their families and trafficked to Russia is also sad(and a war crime), and yet Putin does nothing about that. Somehow I don't think he's actually all that sad about Navalny.

said he had been ready to hand the jailed politician over to the West in a prisoner exchange provided Navalny never return to Russia. Navalny's allies said such talks had been under way.

It's an awful coincidence that the moment they decide to start considering releasing him, that he dies, isn't it? Nevermind the fact that he'd at this point been sentenced to over 20 years in Russian prison and a mere 2 months prior to his death was secretly sent to an arctic circle prison that is essentially a death camp, with none of his team knowing where he was for weeks. No no, forget ALL of those facts and trust Daddy Putin at his word that they were totally going to release him if he hadn't died when he did.

What a load of bullshit. At best, they knew Navalny wasn't doing good and were hoping to release him before he died so they could wipe their hands clean of it. Realistically though, what happened was always the plan.