There is one argument, especially after the 2022 invasion, about Ukraine (and the other non-Russian ex-SSRs) and nuclear weapons. This goes: They gave up their nuclear weapons in exchange for largely meaningless and unenforceable diplomatic agreements, which was a mistake that Ukraine paid for and Kazakhstan might have.
Many informed nuclear commentators have pointed out that the launch codes/infrastructure were still in Russian hands, that Ukraine had no actual control, and that the ICBMs in particular were ill-positioned for deterring their former owners. This is all accurate, as is the staggering cost of making a usable nuclear program during a time of massive political and economic upheaval (Ukraine’s implosion in the 1990s made Russia’s look like a modest recession, and Kazakhstan had effectively no army of its own immediately after independence)
But there is another opposite fallacy, which is that the decision was more or less out of their hands. Because all the nuclear weapons were under Russian control, there was no real choice involved. This is also flawed. The nuclear weapons weren’t immediately usable, but to act like there was a Ward Of Russianism on them is wrong. Ukraine had extensive infrastructure and science on its territory (including a missile plant), while Kazakhstan’s uranium industry meant that it was already over the biggest hump for a usable bomb-the materials.
So it was not technically impossible for the non-Russian SSRs to maintain a nuclear weapons program. You can argue that it was politically and economically so, and probably correctly. But it was not a technical issue. The republics had agency, and they likely prevented a far earlier Russian invasion by relenting.