Finland & Sweden were not controversial for admission and even these took much effort. Hungary has made clear they would never support Ukraine inside NATO. But even if their politics changed to allow it, the Turkish would never allow it, no matter which political party runs Turkey.

But let's say that Ukraine did join NATO. So what? NATO is a defense treaty and a standards organization. Being a member of NATO just makes you a little harder to invade, it is not a threat to non-NATO neighbors. If Russia did not have an "invade your neighbor" mindset, there would be zero problem with all her neighbors being NATO members. That Russia has a problem with the idea of Ukraine inside NATO is an indication that Russia does not respect borders or national sovereignty of her neighbors. That she opposes it is the reason it is reasonably desired.