Trump had four years where he could have just taken a grip and forced a withdrawal.
If Trump hired people who lied to him and he didn't have sufficient awareness on events to realise, he's incompetent. That is the incredibly simple reality. This is a man who apparently hasn't had an intelligence briefing for five months, and for whom the intelligence community had to work hard to get him to pay any attention in the first place. We might note that the Syrian liaison, Jeffrey, does say he effectively "tricked" Trump re the number of troops in Syria (more fool Trump for letting that happen), but the real issue is that they just came up with reasons to not withdraw, and Trump folded. Repeatedly. Because Trump had no real interest in making it happen, and no real aptitude to get it done. He's a child in playpen, making demands about things he doesn't understand and at the mercy of the whim of the adults caring for him for whether they happen
It's about as strong as the notion that the Norwegians are Swedes, or the Belgians are Netherlanders. Or even that the Dutch, Swiss and Austrians are all just Germans. Which is to say, they aren't.
At one point far in the past, in the time when the Norse migrated and formed a ruling class over the Slavs to create the people we called the "Rus", and these were the proto-Ukrainians and proto-Russians, and maybe the Belarusians/ But then they went through a lot of divergence and different development after the Mongols, and they ain't the same any more.
The issue with Eastern Ukraine is really that it has a larger Russian ethnic minority, and stronger links with the neighbouring Russian state. In many ways, the fall of Russian influence in Ukraine also reflects Russians emigrating back to Russia, and that the Russian-connected areas also have a much higher population decline.