I would recommend 'Adapt! On a New Political Imperative' by Barbara Stiegler. The movement away from classical liberalism has been going on for far longer and was by design. It is very important to explicitly separate traditional or classical liberalism from neoliberalism when discussing these things. And just to be pedantic the term liberal should also absolutely be avoided when discussing anything involve impacts from the "new left" movement.

>Why did everyone across the entire political spectrum abandon individualism in the 20-teens

IMO they didn't - at least not explicitly. Individualism has been somewhat illusionary since the progressive era it is just finally coming home to roost. What happened is that the internet finally out ran the ability of the traditional media consensus methods at the national level as the internet generation aged in. So we are sort of in unknown territory where it is not clear any "expert" can play the designated role to drive the consensus required in the neoliberal system.

Where to go from there is an open question but her thesis is that the neoliberal system needs to be adapted in someway. Anyway that is largely the picture of the problem she paints. I'm not doing it justice but it is worth a read to at least place a lot of the problems people are observing in a mental and historical framework.

I think a good step is moving towards federating into smaller communities. The best of those ideas will get adopted by other communities. Basically the fediverse model applied to society. People already have this feeling intuitively and it is playing out with the push back against globalization.