Captain Marvel showed the perks of a Skrull positioning themselves in a position of power, and Ross has been in a pretty sweet power position threatening heroes with the power of the United States government.
I’m not saying Ross is for sure a Skrull in disguise, but I won’t be surprised if he is.
In typical Skrull fashion, this could be done by disguising themselves as authority figures.
People like Thaddeus E. “Thunderbolt” Ross, who have bounced back into the MCU like nothing happened after being gone for so long.