He can play two roles, it's not as simple as either good or bad. Capitalist Democratic leadership that is dedicated more to controlling the party's left wing than defeating the country's extremist right wing has and does enable fascism. This isn't even a remotely controversial take, historically speaking. Trump owes his first presidency to the likes of Clinton and Obama, and yes, Joe Biden, who had had a long career of neoliberalism.
That said, while Biden hasn't been, by any means, a perfect president, he has been far better than I expected, possibly the most progressive president since LBJ. And he is standing, albeit somewhat vaguely, between Trump and the Whitehouse.
But stopping Trump isn't going to stop the slide into fascism. It can only, at best, delay things until the next election. To do that, we need a strong progressive movement to send a true leftist coalition to take over DC, and set a national tone and direction that moves away from the fascist ledge.