Ukrainian is a tough language to learn not least because of the past two centuries of the land's history. Taras Shevchenko (1814-1861), whose literary heritage is regarded as the foundation of Ukrainian literature--and, to a large extent, the legitimization of Ukrainian as an independent language--was jailed and exiled a revolutionary for daring to honor his own language as a a worthy medium of expression. I think any learner of Ukrainian quickly becomes aware of this political resonance in their choice.
In today's world, there are multiple resources for learning this language.
--Duolingo has a short learning tree (which includes ~⅓ the number of lessons as it's French or Spanish counterpart),
--Glossika has a full 5,000 spoken Ukrainian sentences--voiced by one of the harshest speakers of Ukrainian that I have ever heard. It's only free for 7 days, but is a great resource for improving one's ear.
--The UK Ukrainian Language organization is an excellent source for beginning pronunciation and for reading.
--Anna Ohoiko has a beautifully put together collection of language lessons and podcasts at Ukrainian Lessons. This is s free resource, but there are extras that can be added with a charge. This site has been active for a few years now, so there it a lot of content.
--for flashcards, Anki has some useful language decks (though Ukrainian does not rate as one of their top languages). You have to log in to access content. I find the ☀️Ukrainian Language Vocabulary: Illustrated deck particularly good--not least because it is my own creation.
These sources--they subtly contradict each other. Some offer a more Russian influenced Ukrainian, others less so. Between the 20th century diaspora and the last 30 years of Ukrainian independence--the culture and language are unsettled and in transition. A fascinating moment to participate in its study, but also frustrating, mysterious and immense/intense in its implications.
Twin Cities Ukrainian Heritage Festival, "Ukrainian Fashion," September 19, 2021