I wrote 700 page book Immortality that is mostly covering the same topic. But I am afraid it is too long and nobody will read it and it is also in Russian. Therefore, I created GPTs agent-guide that explains content of the book.
This what agent-guide said about eternal dictatorship in my book
If you mean the common objection “if people stop dying, dictators will rule forever”, the book treats “eternal dictatorship” as a rhetorical scare story, not a real argument for keeping death.
Two key points it makes:
• It’s a false “only one solution” move. The objection assumes death is the only way to prevent bad political outcomes (dictatorship, stagnation, etc.). But even if dictatorship is a risk, there are many other levers besides killing everyone on a timer: institutions, term limits, checks and balances, decentralization, transparency tech, enforcement, even exile or incarceration. So “we need death” doesn’t follow.  
• “Eternal dictatorship” is often an exaggeration tactic. The text explicitly lists constructs like “вечная диктатура / infinite boredom / eternal hell” as cases where critics inflate X to infinity while keeping death constant, to make death look “necessary.” 
There’s also a very practical aside: even in a world without aging death, dictators don’t automatically get infinity—they still face coups, replacement, accidents, and competition; the book even remarks that “if there were no death from aging, dictators would rule only ~4 years longer on average, because they’re often overthrown.” 
If you tell me whether you meant this as a philosophical objection (“immortality → tyranny”) or a policy worry (“how do we prevent immortal rulers?”), I can point you to the most relevant chapter/section in the text and summarize that part.
How much it cost?
How much damage if the body temporary returned to room temperature?
What do you think about other methods of chemical preservation which do not require cryogenics?