I'd say the fall of the USSR is also very important to this "mythos", but liberal democracy in the West would likely prevail IMO. A purely absent Hitler TL might see someone else take the mantle of "evilest person" - Stalin and Mao are both very good candidates for this.It‘s actually kind of hard to imagine a modern world without Hitler if you think about it (at least for Europe and the west).
WW2 has basically become the founding mythos for the liberal world order, and Hitler is the black hole around which all political, social and cultural discourse ultimately revolves around. And the further away in time we move from the events of WW2, the more powerful this mythos becomes. I don‘t think it‘s an exaggeration to say that it has taken on quasi-religious characteristics by now, with Hitler as a satanic figure against which all of society has to be constantly on guard.
Hitler‘s shadow is so long that ideological opposition to his ideas serves as legitimization for nearly everything and everyone these days, even people on opposing sides: be it progressives or conservatives, Ukraine or Russia, Israel or Palestine – all of them accuse the other of being the heirs of Hitler. Antifascism is the legitimating ideology of the modern (western) world, and the inherent ‚goodness‘ or ‚badness‘ of any policy is judged by its ideological distance and opposition to Hitler, fascism, and everything connected to them.
So imagining a modern world without WW2 and Hitler is almost like imagining a world without Christianity, Islam or other world religions; it’s like painting in the dark. There are actually not many TLs that really take on this issue on a fundamental level; most just assume that the world would look more or less like ours, with similar values, but different borders.
I do think that the "far-right" would be larger, but also more fractured. We have to remember the most extreme far-rightists are literally called "neo-nazis" and so without Hitler and the infamy of National Socialism across the West, you'd see the right and far right have more diversity IMO; that is of course barring another, similar person comes to power who fill the void Hitler left. IMO the same effect would occur on the left if Communism never came to Russia or China. A good TL that explores this is @Zulfurium 's A Day in July.