When it was a part of the USSR it was mainly called "The Ukraine". Since independence, dropping "the" is preferred. But older people will have heard it called "The Ukraine" most of their lives.

The United States of America, The Soviet Union, The Maldives,

I'm sure there are others

Well we do say The Gambia, The United States, The Republic of Korea...

It means like "the edge" - which is what it was - like "the borderlands". But plenty of places have the in the title optionally

It's a fair peeve, since it calls back to Soviet era bullshit.

But it's gonna take a few more decades before it dies out now that Ukraine is the forefront of resistance, and is likely to be. I think it would have been over and done soon were it not for that. Only older gen-x and older were really using "the Ukraine" on a regular basis that I could tell. Us gen-xers were phasing it out overall just because it's one less word to type.

But with the news being crammed full of both naming versions, it's gonna drag it out

In German we use the article only for feminine countries. Yes, everything has a gender in German, even countries. We say "Die Ukraine", but just "England" and not "Das England".

But English has lost its grammatical genders some 800 years ago, I guess that's too long ago for being the reason.