I mean by their definitions everyone who was anyone was a supremacist and eugenicist back then. But not the way they think.
Lindbergh was actually a white supremacist. During WWII he was suspicious of Russians as "part Asiatic" and gave speeches about our racial links to Europe...you can thank Lindbergh for weird leftists insisting on importing zillions of African refugees to Maine. Basically the suspicion of white people and the insistence "white people have no culture" is an overreaction to the types of things Lindbergh & Henry Ford were saying at one point. Also interesting because the USSR basically defeats Hitler, that defeat basically happens from the East not the West. For all the credit the US & UK give ourselves, I mean, without Canada training British fighters and the Russians refusing to give up in Stalingrad we're all speaking German today.
Lindbergh also had some kind of weird fertility fetish. You know how Elon Musk keeps siring children because he thinks he's an amazing specimen, not just an autistic with a rich dad who should steer clear of the gene pool? Lindbergh did actually father children with Northern European women outside of his marriage because he thought he was some kind of uber-man and the world needed more of his DNA in the gene pool. He had one very long-term affair and also purposely fathered children by his affair partner's sister, all kinds of weird shit. He had like 7 extra kids in Europe, no one said anything about it until after his widow died. His youngest kid with his legal wife has written about meeting some of the half-siblings.
Of course he didn't like, spend much time with these extra children he fathered. He was introduced to them as Mr So-and-so, they didn't even know he was their dad initially. Having 3 unacknowledged babymamas on the side also probably didn't help his marriage to Anne Morrow Lindbergh or his relationship with
their many kids. That's a hell of a distraction/time commitment. And just...most of his kids seem to be pretty average. Some of the ones with the Lindbergh name are involved in aviation or are published writers but that's probably more due to nepotism than anything else. His sidepiece kids have mostly not even come forward, two of his side-families refused to speak to the press. Those kids probably aren't notable in their fields or someone would've been like, "That's the guy who looks just like Charles Lindbergh and his mom used to hang around with him all the time....hmm" You know like the Usher - Ben Vereen rumors.
Lindbergh's wife was the daughter of an ambassador and a published author in her own right; she also worked as his navigator or co-pilot on some of his flights. Her book "gift from the sea" is reasonably famous and your public library probably has a copy of it. If I'm not mistaken it's still in print.
Lindbergh was a very, VERY strange man. I don't think he conspired to kill his own child but one conspiracy theory is that the child was 'imperfect' in some way so he staged it. I don't think that's true and his wife Anne certainly seemed legit devastated about the loss of her baby; he's kind of a jerk but I truly hope he wouldn't do that to her and his own child. There's not real proof the 2 immigrants did it but I do think someone who resented Lindbergh probably did do it. As I said, he was a strange man and basically a jerk.