Errr... Well, its a misconception that any amount of radioactivity leads to excess deaths and cancers.
There are many places on earth with hell lot of radioactivity occuring naturally. I lived in hilly parts of Vancouver for sometime and there is radon in soil there and if you go out with a gieger counter you see high radioactivity in many places including schools. Secondly, Hiroshima and Nagasaki are pretty decent places now after 20 kilotonnes of explosion in which most of radioactive material was blow around. Modern warheads use boosting which ensure most of the fuel in burnt up. Cancer rates in Japan are not exactly sky high as compared to rest of the world.
Hiroshima and Nagasaki are ground burst, and the technology of delivery is not the same level as today, you cannot compare the 2 bomb in 1945 to what would have been done today, I can say even the severity is underestimated if we are using 1986 Chernobyl disaster
I mean, sure, if you think nuking Kyiv is not big deal to Russia or Belarus, go ahead, please do. But I was in the Army, and I went thru CBRN training, and my training tell me otherwise. I wouldn't do it if I was on the button, but well, you have your own opinion, just be glad when that did happen, you don't live in Moscow.
Will UK go for a nuclear war with Russia over inconsequential countries like Finland and Sweden? I doubt it. The extent of defence pacts is not enough and is neither comprehensive enough like NATO. Besides, if UK attacks Russia first (because of its obligations of its own treaty), NATO is not obliged to involve itself. That is the exception in NATO charter. We have seen already, US/UK/NATO are not in a mood to fight directly with Russia in any capacity.
The same question would applies to Russia as well, would Russia want to risk a nuclear war with UK or NATO over Sweden and Finland? How do you know NATO will not response?
And lol, you obviously confused between "don't want to fight" Russian directly and "don't need to fight" Russian directly. After you seeing how Russia only been able to take 9% of Ukraine in 100 days, do you really do think Russia would have any chance facing off NATO? Before you say NATO don't dare to do anything, they are sending advance weapon to Ukraine for the express purpose of killing Russian soldier, for all intend and purpose they are already at war, I mean, I have seen war started less than this, I wouldn't be surprise if Russia really go after NATO. NATO already risk actually going to war by acting OVER the line of neutrality. So no, what you said about NATO is not in the mood to fight Russia directly is not true at all.