It’s complicated because ‘social democracy’ and ‘democratic socialism’ are two distinct ideologies, who’s definitions have flipped throughout history, and who’s biggest proponents (in the US at least) get it backwards.

Social democracy isn’t a form of socialism since it’s still capitalism, albeit one with guardrails. Most people that identify as democratic socialists – aside from social democrats misusing the term – are socialists that want to draw a contrast with Marxism-Leninism and other perceived ‘authoritarian’ forms of state socialism. But it’s hard to define a concrete definition for the term since people use it as an umbrella term, including it’s adoption by some state socialists.