I'm a leftie from the US and I agree with you that it's a distinct possibility.
I've felt for years now, before Trump got elected actually, that we're heading toward an American Kristallnacht.
But then, I'm a "flaming libtard" who grew up in the conservative evangelical south so....do the math there.
It's the preachers.
If you've got a brain in your head, some of those fuck's preaching will raise the hairs on the back of your neck up for ya.
Seeing all your neighbors, friends, and family responding to the stoking of atrocities--cause that's what it is-- like it's harmless and family oriented entertainment will raise your hackles.
And that's been going on since well before Trump.
I do disagree with you on a few points.
I think the bloodletting will be against LGBTQ and women first. They'll eventually get back around to Black people again because that's the original purpose of the Klan and nothing's changed there. Not all far right militia types are Klan members but Klan are allies to them. Plus, the current rhetoric is currently far more directed toward LGBTQ and women than Black people. The "we're coming for you" overt threatening rhetoric. There's been a spate of spite execution style murders, lynching type murders in other words, against LGBTQ and women perpetrated by low IQ far right types fomented to violence.
The same type of violence against Black people is still, for the most part, contained within the police force. It's not spilling out into the public and doesn't seem likely to. Yet. Not that state sponsored terrorism isn't bad enough. And there have been some lynchings and attempts that are racislly motivated.
My point is, if it's a wave as you describe, the wave will mlst likely follow the rhetoric. If it's a stream of attrition, it will be persistent but random attacks against anyone marginalized.
Secondly, while it's true what you said about Republicans owning most of the guns, you ignore that it's excess in many cases, like a car collector, just showing off. You can only fire one or two at a time in a situation. So, a lot of those guns aren't going to be in play during a wave of violence. They can't be. And the left IS armed.
Further, they tend to congregate together periodically and predictably and they're so loud, it's no secret where and exactly who they are.
There will be many on the left uselessly waving placards, it's true. But. I think you miss how many on the left are ready to step away from protests that don't change things.
And they're not as fat, on average, as the far right white dude you describe.