Well for the most part if we want to have a less context-dependent measure, with some caveats

The "left" vs "right" dichotomy is inherently context-dependent though. Objectively, it's a terrible way to compare ideologies without context. Personally I find 8axis to be pretty decent instead. Unfortunately, the world on average is more authoritarian & conservative than the US, your scale may be an accurate representation of the lemmy overton window.

What’s fucked is most people think of prominent historical figures...

Because they think that the changes they achieved were good, and they see themselves as good, and they consider themselves american liberals.

Either way there is no chance that democratic socialists are as extremist as national conservatives.

In the global overton window? Yes way.

What pushes democratic socialists a full point towards the fringe compared to social democrats?

From wikipedia:

Democratic socialism is a left-wing set of political philosophies that supports political democracy and some form of a socially owned economy, with a particular emphasis on economic democracy, workplace democracy, and workers' self-management within a market socialist, decentralised planned, or democratic centrally planned socialist economy.

Unlike social democrats, democratic socialists want to do away with private ownership and market economies. For the record, the US democratic party are not social democrats.

I'll finish off with my take on the infamous "what's a liberal?". In hindsight it was probably a poor choice of words as there is no such thing as a "pure" liberal. The basic liberal value is freedom. To me, that includes freedoms of thought, speech, press (i.e writing, possibly also digital), organization, bodily autonomy and lastly ownership. Everything else is a product of how to interpret those freedoms and how to implement them.

"Pure liberals" would most of all strive to uphold these individual freedoms, though their solutions when different peoples rights clash may be different. A "pure" liberal strives for a balance maximizing freedoms of individuals whilst simultaneously minimizing infringements from both government and private actors. To me, neither ancaps nor libertarians are liberal. Libertarians prioritize small government to the point where it is incapable of protecting individual rights from abuse by third parties whilst ancaps prioritize property rights over individual freedoms.

Soclibs and libcons both limit freedoms somewhat in favour of other values.