Bernie would have done worse for sure. Bernie doesn't have the political smarts to know that calling yourself a "democratic socialist" does not make you electable to be President of the US. Or maybe he knew but didn't care and didn't actually care enough about winning the nomination to distance himself from socialism and say he is not a socialist. Bernie isn't even a real socialist, nor would that have been part of his campaign, but if Sanders refused to distance himself from it, the Republicans would have acted like defenders of capitalism against socialism. they would have tried to make that the choice of this election, not progressive ideas vs crazy conservatism, but simply capitalism or socialism. Down ballot Dems would have been asked if they are socialists. Gary Johnson would have capitalized on it, probably doubling his votes. Jill Stein would probably still have run, and focused her campaigning against Bernie just like she did with Hillary. It would have been twice the shitshow that was this election.

tl;dr the Democratic Party was never going to nominate someone known as a "democratic socialist", even if he was a Senator. If he wanted to win he should have said he wasn't.