ukraine.ua has, for a long time, been run by the Ukrainian government, has been registered in 2012 according to whois, and is owned by the Ukrainian patent office,
created: 2012-09-28 12:19:12+03
modified: 2021-10-28 12:23:01+03
expires: 2022-09-28 12:19:12+03
organization: Ukrainian Trademarks Ltd
organization-loc: ТОВ "Українські торговельні марки"
abuse-postal: Ukraine 03087 Kyiv 18-A Erevanskaya Str., kv. 17
abuse-postal-loc: Україна 03087 Київ вул. Єреванська, буд. 18-А, кв. 17
On that website, there's a prominent link "do not look away from the war" that links to
war.ukraine.ua, which again has a link "Donate to Ukraine" to
war.ukraine.ua/donate , which again mentions, in its text,
The same site has instructions for how to contact Ukraine embassies for voluntary military services. Which means that, from time to time, individuals will turn up at embassies mentioning the web site, which means Ukraine will at least be aware of the site.
The site also says, in the bottom row:
This is the official website of Ukraine. The information is verified by the Ministry of Foreign Affairs of Ukraine
While this is not a 100% proof, in order to be fake, the scammer would need to have gotten control of the domain back in October 2021, with the Ukrainian government unaware, unwilling, or unable to get it back since then. This scenario sounds quite inconceivable to me. So I believe that
ukraine.ua is, in fact, run by the Ukrainian government, and, by extension, the link to
bank.gov.ua is legit.