Some logical nits:

• Early on you mention physical attacks to destroy offline backups; these attacks would be highly visible and would contradict the dark forest nature the scenario.
• Perfect concealment and perfect attacks are in tension. The AI supposedly knows the structure and vulnerabilities of the systems hosting an enemy AI, but finding these things out for sure requires intrusion, which can be detected. The AI can hold off on attacking and work off of suppositions, but then the perfect attack is not guaranteed, and the attack could fail due to unknowns.

Other notes:

• Why do you assume that AIs bias towards perfect, deniable strikes? An AI that strikes first can secure an early advantage; for example, if it can knock out all running copies of an enemy AI, restoring from backups will take time and leave the enemy AI vulnerable. As another example, if AI Alpha knows it is less capable than AI Bravo, but that AI Bravo will wait to attack it perfectly, AI Alpha attacking first (imperfectly) can force AI Bravo to abandon all previous attack preparations to defend itself (see maneuver warfare).
  • "Defend itself" might be better put as re-taking and re-securing compromised systems; relatedly, I think cybersecurity defense is much less of an active action than this analysis seems to assume?
• An extension of your game theory analysis implies that the US should have nuked the USSR in the 1950s, and should have been nuking all other nuclear nations over the last 70 years. This seems weird? At least, I expect it to not be persuasive to folks thinking about AI society.
• The stylistic choice I disagree with most is the bolding: if a short paragraph has 5 different bolded statements, then... what's the point?