Would I like to have a system of national insurance similar to what is in Canada or Norway to France? Yes!!!! Do I think it’s realistic in the US now?? Nope. Look at the current court battles over women’s health care under the ACA. Funny how there’s never any quarrel about whether a man can get a vasectomy or have prostate surgery. That’s where we are. It’s frustrating and infuriating but it’s reality.
And you're standing in the way of the one candidate (Bernie) who is trying to make it happen, because you don't like some of his supporters and think he "doesn't get along" with others. Guess what? Yes he can. And guess what else? He doesn't have to get along and go along with them as Democrats have been folding to the Republicans over and over again.
He can do something novel for the Democrats and actually take a hard stand with the Republicans, and appeal to their voters, with whom many of his policies are polling very well (better than I think you realize; look it up). Republicans bulldoze. Guess what? Democrats can too. And when Republicans (and when corporate democrats) stand in the way, go straight around them directly to the people in their district.
Republican voters and Trump voters have a lot of brainwashing and propaganda and tribalism to see through (so do Clinton Democrats btw), but they are NOT the idiots or the evil monsters you may take them for. They can be appealed to and their minds can be won, but not if you come at these voters with a hostile approach, speaking of "deplorables" etc. Calling any voter that accomplishes nothing. Save that for what you call the people standing in the way of what the people want.
Bernie and Yang are to the far left, further left than you say you think is possible to make happen, yet these two have more independent and cross over republican and (ex)Trump voter supporters than Biden, Klobuchar or any of the establishment corporate Democrats do. These establishment democrats are seen by these voters as the "Swamp" Trump spoke to them about to win their votes.