Olena Zelenska did NOT target the UK.
She was being interviewed by Laura Kuenssberg for the BBC, who directed the conversation to the situation in the UK specifically (as the interview was made to be broadcast to a UK audience) and asked her what she would say to people in the UK who sympathise with Ukraine but also feel the squeeze at home to the extent that they are desperately scared for their families. She would say the same thing when talking to the press from ANY allied country when asked a similar question. Here's a recent interview with Italy's Corriere della Sera, just for example.
Zelenska says that global trends will impact all of us no matter what country we're in (she uses COVID as another example). Her argument is that international support of Ukraine will help push back Russian aggression: "if the (international) support is strong, this period will be short."
I can't say that she's right, because I can't see the future. But I believe and hope that she is right. But whether or not she is, what people have known in central and eastern Europe for a long time (Poland, for example, has formally treated Ukraine as the victim of an aggressive international war ever since Russia annexed Crimea in 2014) has become way too obvious to ignore in Western Europe: we can combat Putin now in Ukraine, when we can still sort of formulate that as a "choice", or we deal with it when he attacks a NATO country and we're all formally obligated.
Of COURSE anyone in the UK shouldn't feel guilty ranting a bit about current circumstances and how they impact you, your family, and your community; everyone needs to let off steam. You shouldn't feel guilty about asking the UK government to take care of its people. You shouldn't feel guilty about using resources that are available to you or about taking joy in the moment or in daily life. But Zelenska isn't asking anyone to feel guilty. What she is saying is that IF you think it's wrong for Russia to invade other countries and commit atrocities and war crimes, then it's wrong even if standing up to it hurts. It's not an "either or", it's a "both and".
The First Lady and President posed for Vogue whilst her people were starving, dying, fighting and being raped. What's your point, @AbsentinSpring? The more attention the situation in Ukraine gets internationally, the more support is mustered internationally. I'm absolutely sure Zelenskyy has more important things to do than pose for Vogue, but if that's what helps Ukraine then he does it.