You don't justify or define "severe degradation of security" just assert it as a fact.
The advent of nuclear weapons has meant 75 years of relative peace which is unheard of in human history, so quite the opposite.
Given that AI weapons don't exist, then you've just created a straw man.
I do claim that it is obvious that widespread acquisition of nuclear weapons by smaller states would be a severe degradation of security. Among other things, widespread ownership, would also mean that militant groups would acquire it and dictators would use it as a protection leading to an eventual use of the weapons.
Yes, the danger of AI weapons is nowhere at that level of nuclear weapons yet.
But, that is the trend.
https://www.nytimes.com/2023/07/25/opinion/karp-palantir-art...
For smaller countries nukes represented an increase in security, not a degradation. North Korea probably wouldn't still be independent today if it didn't have nukes, and Russia would never have invaded Ukraine if Ukraine hadn't given up its nukes. Restricting access to nukes is only in the interest of big countries that want to bully small countries around, because nukes level the playing field. The same applies to AI.
Regarding an increase in security with nukes, what you say applies for exceptions against a general non-nuclear background. Without restrictions, every small country could have a weapon, with a danger of escalation behind every conflict, authoritatrians using a nuclear option as a protection against a revolt etc. The likelihood of nuclear war would be much more(even with the current situation, there have been close shaves)
The danger of something like AI+drones (or less imminent, AI+bioengineering) can lead to a severe degradation of security, like after the invention of nuclear weapons. A degradation in security, which requires collective action. Even worse, chaos could be caused by small groups weaponizing the technology against high profile targets.
If anything, the larger nations might be much more forceful about AI regulation than the above summit by demanding an NPT style treaty where only a select club has access to the technology in exchange for other nations having access to the applications of AI from servers hosted by the club.