NY Times today (26 May 2023): If a Divided Germany Could Join NATO, Why Not Ukraine.
West Germany joined in 1955, with outstanding territorial disputes yet unresolved.
Austria was also divided, the Soviets left on condition that Austria could not join NATO.
And there are still no NATO forces based in the former territory of East Germany. This is based on the treaty made with Gorbachev that Russian propagandist try to say we broke by expanding NATO. But we have abided by it to this day, even though it was made obsolete by Poland and the Baltics NATO membership.
Under the same model, NATO bases in Kharkiv, Kyiv, Kherson and Odesa would be fine.