That’s actually the accepted term. Though it’s usually abbreviated as AMAB (or AFAB). Having been assigned a particular gender does not make it so.
And that is the difference @We_re_wolves_not_werewolves. Saying someone is “biologically male” is inaccurate if they have undergone physical changes that alter their sexual characteristics. Human sexual expression is mediated by hormones, not by chromosomes.
This is not true of all animal species, btw. An example may help make the distinction above more clear. There are birds out there which have white feathers on one side of their body, and red feathers on the other. This is a striking example of sexual chimerism: the left half of their body has one set of sexual chromosomes, while the right has another. And because those chromosomes define sex, they genuinely appear half male and half female.
Sexual chimerism also occurs in humans. But this sort of pattern is impossible. Since hormones determine sex, the XX cells and XY cells are not so easily distinguished. You don’t wind up with, say, one breast or anything like that. In fact, all your cells can be XY, and yet, if you have complete androgen insensitivity syndrome, you can wind up with extreme feminine characteristics.
Anyways, saying I’m AMAB, that I was assigned male at birth? That’s a factual claim. They put an M on my birth certificate. From birth I was treated as male. I presented as a boy and eventually as a man.
Now, I will admit that this fact can sometimes cause some dysphoria is some trans femmes. It does not for me, but being reminded of such can rarely trigger a dysphoric reaction (especially in those who are still early in their transition). So I wouldn’t use it unless necessary.
But I am unaware of a better term for when it is. Every other term I have heard just isn’t accurate.