Well, aside from blaming it on Marxists specifically, I can't disagree with much of what you said. I'm a lefty, always have been, hence why I've got a better eye on what goes on internally in the movement than you probably would. And there have been some fucking gross developments in the last four to eight years, I can tell you.
I would divide the US left movement into three main strains currently. Of course people don't fall cleanly into one group or another (because people are complicated), but they go more or less like this:
1.) Mainstream liberals (the Clinton Wing) - Neoliberals who are interested in social virtue signaling, i.e. socially liberal conservatives. These people have been in power in the Democratic party since Bill Clinton at least. They used to be for free speech, but the rise of Donald Trump and uncontrolled messaging of ideas through social media has changed that completely and they now want speech to be regulated, so that no new Donald Trump or Bernie Sanders may rise again... which (hopefully) will backfire in their faces. These people are also the ones which made RussiaGate a thing during the last five years, to distract from them losing to Donald Trump and a 1000 seats in different legislatures during the Obama years. The Clinton wing is socially authoritarian left and economically completely neoliberal.
2.) The woke crowd (the AOC wing) - Okay, this will sound kinda weird, but since gay rights have been established during the Obama years, I've noticed a definite slide towards authoritarian speech regulation coming from the woke sector of the left, where they actively want to forbid wrongthink in their own group and, of course, everyone else outside of their group as well. There are a lot of witch hunts internally for people who dissent, cancel culture has become rampant, peoples lives are being ruined, and so on. I think this is the group you think to be Marxists, but I personally would like them more to Stalinists. One recent development which exemplifies this is the issue of trans rights, where people who just think that trans women (i.e. former men) who are physically still men, with all the physical advantages that brings, should not be allowed to compete in professional sports against women, are then labeled as TERFS (Trans-exclusionary radical feminists), like Martina Navratilova or Tulsi Gabbard. Which is nuts, because of course women shouldn't have to professionally compete against trans-women who are physically still men. But, nooo, woke ideology trumps logics for those people.
This group also has become completely unhinged during the four years of Donny Trump and now demand censorship for everybody who does wrongthink. It appears many social media companies also have vast tracts of employees of this kind, who internally now pressure for the full censorship powers to be deployed. Personally, I view this group as the most destructive force in left politics I've seen in my lifetime, since they now hold vast power in the movement overall and their fanaticism and authoritarianism is antithetical to my beliefs. Honestly, I would not be surprised at all if the American intelligence community came up with the idea to foment this kind of ideas to destroy the left internally. This wing of the left is socially authoritarian left and economically between left and neoliberal.
3.) The economic left (the Bernie wing, at least until he turned out to be a giant cuck for Joe Biden) - "My" (inasofar that I agree with their ideas, being from Germany) wing of the movement, who generally wants to make life better for everyone, by taking some money away from the ultra-rich and rich and better distribution of goods and services overall. There are of course varying degrees of "how much" that would be. The whole woke agenda is seen here as a giant distraction from actually helping people achieve more economic equality. Which would also help to lessen racism, because much of racism comes out of people being afraid of people of other ethnicities taking away their social status. This wing is normally socially libertarian and economically left.
I fall down on the social democratic divide of the economic left, where people should have healthcare as a government service, free higher education, some sort of monetary government help during times of unemployment and a decent pension, i.e. how Germany was before the neoliberal reforms of the Schröder government (which, of course, was when the social democratic party was in power, because fuck the ninetees neoliberal bullshit. Fucking neoliberal submarines in the left parties, man).
Anyway, currently the liberal and woke wings are in the positions of power (government, media) and the economic wing, which has always been the underdog strain in the USA after Franklin D. Roosevelt, is still struggling with Bernie cucking out after Super Tuesday and letting Biden waltz to the nomination, especially due to the crushing disappointment this produced. It really looked for a while as if, for the first time in seventy years, there would have been a chance to take the USA (and therefore the world) in an economically and ecologically better direction, and to be denied this so close to the finish line and have the champion of the movement betray them at the last moment was fucking devastating. The project to take over the Democratic party with people like AOC, who are not beholden to corporate donors, has also failed, since AOC and the squad have turned out to be aligned with the woke wing of the party and also want to further their careers internally (AOC, specifically, who I've seen trying to undermine any other female politician who could be a star in the party, like Tulsi, because she wants to be president one day). And that is a bad thing, because, as you said, the first two wings have combined to enforce their authoritarian demands after the capitol riots. The economic left now is rudderless and with no viable path to effect change or exert power in the US.
I'm very concerned that there will be a woke/neoliberal hysteria resulting in bad censorship laws and, of course, a counterrevolutionary movement by conversatives who are being squeezed out of public discourse. "Taxation without representation" was the cause of the American revolution, after all. And lets not forget that there is an eviction crisis looming, due to millions of people having not paid their rents for months on end. Social unrest on a large scale is coming to the US, IMO, and you are not wrong in the least in stocking up on ammo and supplies.
And, yeah, some lesser variation of this will probably come to Europe as well. While everything here is much less extreme than in the US, we also got a woke movement (still much smaller than the mob in the US), we got neoliberals everywhere in government (basically every party in Germany but The Left (yep, that's their actual name) is neoliberal). Both those groups like to mimic what their larger counterparts in the US do, so I expect some abridgement of liberty of speech to be implemented here as well. And while I am mostly in agreement with the measures taken against COVID-19, I am always concerned that measures of civil liberty abridgement are taken too far.
All in all, interesting times to live in, as the Chinese curse goes.
