“Classic liberalism was a stepping stone to modern liberalism.”
Maybe we have different definitions of Classic Liberalism. When I was younger, Liberalism was, essentially, what we now call Libertarian. That is, people were free to do whatever they want, provided that they didn’t infringe on the rights and property of others. The sole purpose of government was to protect the rights of individuals to do whatever they like while ensuring that the rights and property of others weren’t violated.
That is not a stepping stone to modern liberalism. It is the opposite of modern liberalism. One way in which it could be thought of as a stepping stone to modern liberalism is because the Socialist/Progressives stole the name “Liberal”, which used to mean minimal government and maximum individual freedom. They turned it on its head to mean maximum government and minimal individual freedom.
It would be nice if we could constrain individualism as classical liberals and libertarians believe we can, but that is a utopian belief.
We can see where a focus on individualism has led to relativism and subjectivism.
Yes, communitarian/authoritarian beliefs have their own downsides, but individualism is not without its faults especially if taken to the extreme, e.g. gender fluidity, gay marriage, abortion, mass migration, crony capitalism via lobbying, etc.
A Classic Liberal was an anti-Statist Anti-Monarchist.
A Modern Liberal is a Marxist Statist.
180 degree phase shift since the founders lived.