This. Most Western countries don't actually have a 'Right-wing' in the true sense. They merely have two competing groups of Leftists, with one less extreme than the other. This less extreme wing of Leftism calls itself the 'Centre' (e.g. the German CDU or British Tories) or 'Right' (e.g. the US Republican Party) simply because it is defining itself relative to the more extreme wing (i.e. if they're Left, well, we're something other than Left and thus are 'Centre' or 'Right').

Both obviously operate from within the same 'discourse' ('worldview' or 'bubble' as you put it), e.g. everything we dislike is 'fascistic', the other side are the 'real racists', the other side are the real enemies of 'freedom' and 'equality', etc. They don't think from outside of that discourse, e.g. that it doesn't actually matter whether something is 'fascistic', 'racist', 'unequal', etc. If they think these things matter, they've already internalized Leftism.

You went through a sort of mainstream faux-Right false opposition phase? Where you saw the Left as being the real Far-Right like all faux-Rightists do, i.e. progressives/liberals are the 'real Nazis and fascists', they used to support eugenics which inspired the Nazis, they always talk about animal rights, environmentalism and socialized this and that which the Nazis also did to varying degrees, so therefore Clinton, Corbyn, Biden, Merkel and Macron are the new Hitlers, and perhaps that the EU is the Fourth Reich?

I never went through that phase (or any Leftist phase), but it does seem that a lot of people who reject the discourse actually started from within it, embracing worldviews that seem utterly outrageous when viewed from outside of the 'bubble'. Of course, I think the 'bubble' is somewhat inescapable as it permeates almost everything, but people considered 'Right-wing extremists' are far closer to escaping the bubble than anyone else. Indeed, 'extremist' often seems to be used as a label by people within a bubble to refer to people who are close to escaping it. If too many people become 'extremists', then the whole bubble pops—rebellion occurs. So people need to be kept within the bubble, away from 'extremism', through processes of indoctrination and socialization. The education system, media, etc. all work to preserve the bubble, e.g. by misinterpreting everything in ways that do not threaten it. For example, Antifa violence is misinterpreted farcically as 'actually being Far-Right violence in disguise'. Therefore what would normally threaten Left-wing hegemony now reinforces it, i.e. the 'Far-Right' is the 'real' problem, not us Leftists. Similar to how the Democrats opposed travel bans, supported the BLM protests and were largely 'anti-vaxxers' until Biden was elected (we don't trust Trump's vaccine, it's being rushed in time for the election), i.e. all things that would exacerbate any pandemic's spread. Of course, this reality is buried and replaced by a false narrative ('Trump is responsible for Covid'), which supports (helps get Biden elected) rather than damages the bubble.